Image forming optical system and electronic image pickup apparatus using image forming optical system

ABSTRACT

An optical system has a positive lens group, a negative lens group, and an aperture stop. The negative lens group is disposed at an object side of the aperture stop and has a cemented lens, and in a rectangular coordinate system in which a horizontal axis is Nd and a vertical axis is νd, when a straight line indicated by Nd=α×νd+β where α=−0.017 is set, Nd and νd of at least one lens forming the cemented lens are included in both an area determined by a line when a lower limit value is in a range of expression (1 a ) and a line when an upper limit value is in a range of the expression (1 a ), and an area determined by expressions (2 a ) and (3 a ): 1.45&lt;β&lt;2.15 (1 a ); 1.30&lt;Nd&lt;2.20 (2 a ); and 3&lt;νd&lt;12 (3 a ); where Nd denotes a refractive index, and νd denotes an Abbe&#39;s number.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based upon and claims the benefit of priority from the prior Japanese Patent Application Nos. 2005-264601 filed on Sep. 13, 2005, 2005-264605 filed on Sep. 13, 2005, 2006-241446 filed on Sep. 6, 2006, and 2006-241488 filed on Sep. 6, 2006, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an image forming optical system which is used in an extremely small image pickup module, and an electronic image pickup apparatus which includes the image forming optical system.

BACKGROUND ART

In recent years, a digital camera has been widely used as a next generation camera replacing a silver salt 35 mm film camera. Recently, there has been an increasing reduction in a size, and thinning of a digital camera. Moreover, a camera function (hereinafter called as an ‘image pickup module’) has been mounted even in a portable telephone, the use of which has also been increasing widely. For mounting this image pickup module in the portable telephone, an optical system has to be smaller and thinner than an optical system of the digital camera. Particularly, in a zoom lens, the reduction in size and the thinning have been sought. However, a zoom lens having a size reduced to be capable of being mounted in the portable telephone has not been known much.

As a typical means for reducing the size and thinning the zoom lens, the following two means can be taken into consideration. In other words,

A. To use a collapsible lens barrel, and to accommodate the optical system in a thickness (depth) of a casing. This collapsible lens barrel is a lens barrel having a structure in which, the optical system protrudes from a camera casing at the time of taking a picture, and is accommodated in the camera while carrying.

B. To accommodate the optical system in a direction of width or in a direction of height of the casing by adopting a dioptric system. This dioptric system is an optical system having a structure in which, an optical path (optical axis) of the optical system is folded by a reflecting optical element such as a mirror or a prism.

However, in the structure in which the abovementioned means A is used, the number of lenses forming the optical system or the number of movable lens groups is still large, and it is difficult to carry out the reduction in the size, and the thinning of the casing.

Moreover, in the structure in which the abovementioned means B is used, it is easy to make the casing thin as compared to a case in which the means in the abovementioned A is used, but an amount of movement of the movable lens group at the time of zooming, and the number of lenses forming the optical system tend to increase. Therefore, volumetrically, it is not at all suitable for the reduction in size.

DISCLOSURE OF THE INVENTION

An image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop,

the negative lens group is disposed at an object side of the aperture stop,

the negative lens group has a cemented lens which is formed by cementing a plurality of lenses, and in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set,

Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and an area determined by following conditional expressions (2a) and (3a). 1.45<β<2.15  (1a) 1.30<Nd<2.20  (2a) 3<νd<12  (3a)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.

Moreover, an image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop,

the negative lens group is disposed at the object side of the aperture stop,

the negative lens group has a cemented lens which is formed by cementing a plurality of lenses, and

in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set,

Nd and νd of at least one lens forming the cemented lens are included in both of area namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1b), and a line when an upper limit value is in a range of the following conditional expression (1b), and an area determined by following conditional expressions (2b) and (3b). 1.45<β<2.15  (1b) 1.58<Nd<2.20  (2b) 3<νd<40  (3b)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.

Moreover, an electronic image pickup apparatus of the present invention is characterized in that the electronic image pickup apparatus includes an image forming optical system mentioned in any one above, an electronic image pickup element, and an image processing means which is capable of processing image data obtained by image pickup by the electronic image pickup element of an image which is formed through the image forming optical system, and outputting image data in which, a shape is changed upon processing, and in which the image forming optical system is a zoom lens, and the zoom lens satisfies a following conditional expression at a time of infinite object point focusing. 0.7<y ₀₇/(fw·tan ω_(07w))<0.96

where, y₀₇ is indicated as y₀₇=0.7 y₁₀ when, in an effective image pickup surface (surface in which, image pickup is possible), a distance from a center up to a farthest point (maximum image height) is let to be y₁₀. Moreover, ω_(07w) is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface in a wide angle end up to a position of y₀₇.

According to the present invention, it is possible to achieve a thinning and a size reduction of a volume of the image forming optical system, and further to have both of a widening of an angle and a favorable correction of various aberrations in the electronic image pickup apparatus of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view along an optical axis showing an optical arrangement at the time of an infinite object point focusing at a wide angle end of a zoom lens according to a first embodiment of the present invention;

FIG. 2A, FIG. 2B, and FIG. 2C are diagrams showing a spherical aberration, an astigmatism, a distortion, and a chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the first embodiment, where, FIG. 2A shows a state at the wide angle end, FIG. 2B shows an intermediate state, and FIG. 2C shows a state at a telephoto end;

FIG. 3 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a second embodiment of the present invention;

FIG. 4A, FIG. 4B, and FIG. 4C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the second embodiment, where, FIG. 4A shows the state at the wide angle end, FIG. 4B shows the intermediate state, and FIG. 4C shows the state at the telephoto end;

FIG. 5 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a third embodiment of the present invention;

FIG. 6A, FIG. 6B, and FIG. 6C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the third embodiment, where, FIG. 6A shows the state at the wide angle end, FIG. 6B shows the intermediate state, and FIG. 6C shows the state at the telephoto end;

FIG. 7 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fourth embodiment of the present invention;

FIG. 8A, FIG. 8B, and FIG. 8C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fourth embodiment, where, FIG. 8A shows the state at the wide angle end, FIG. 8B shows the intermediate state, and FIG. 8C shows the state at the telephoto end;

FIG. 9 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fifth embodiment of the present invention;

FIG. 10A, FIG. 10B, and FIG. 10C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fifth embodiment, where, FIG. 10A shows the state at the wide angle end, FIG. 10B shows the intermediate state, and FIG. 10C shows the state at the telephoto end;

FIG. 11 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a sixth embodiment of the present invention;

FIG. 12A, FIG. 12B, and FIG. 12C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the sixth embodiment, where, FIG. 12A shows the state at the wide angle end, FIG. 12B shows the intermediate state, and FIG. 12C shows the state at the telephoto end;

FIG. 13 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a seventh embodiment of the present invention;

FIG. 14A, FIG. 14B, and FIG. 14C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the seventh embodiment, where, FIG. 14A shows the state at the wide angle end, FIG. 14B shows the intermediate state, and FIG. 14C shows the state at the telephoto end;

FIG. 15 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eighth embodiment of the present invention;

FIG. 16A, FIG. 16B, and FIG. 16C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eighth embodiment, where, FIG. 16A shows the state at the wide angle end, FIG. 16B shows the intermediate state, and FIG. 16C shows the state at the telephoto end;

FIG. 17 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a ninth embodiment of the present invention;

FIG. 18A, FIG. 18B, and FIG. 18C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the ninth embodiment, where, FIG. 18A shows the state at the wide angle end, FIG. 18B shows the intermediate state, and FIG. 18C shows the state at the telephoto end;

FIG. 19 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a tenth embodiment of the present invention;

FIG. 20A, FIG. 20B, and FIG. 20C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the tenth embodiment, where, FIG. 20A shows the state at the wide angle end, FIG. 20B shows the intermediate state, and FIG. 20C shows the state at the telephoto end;

FIG. 21 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eleventh embodiment of the present invention;

FIG. 22A, FIG. 22B, and FIG. 22C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eleventh embodiment, where, FIG. 22A shows the state at the wide angle end, FIG. 22B shows the intermediate state, and FIG. 22C shows the state at the telephoto end;

FIG. 23 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twelfth embodiment of the present invention;

FIG. 24A, FIG. 24B, and FIG. 24C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twelfth embodiment, where, FIG. 24A shows the state at the wide angle end, FIG. 24B shows the intermediate state, and FIG. 24C shows the state at the telephoto end;

FIG. 25 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirteenth embodiment of the present invention;

FIG. 26A, FIG. 26B, and FIG. 26C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirteenth embodiment, where, FIG. 26A shows the state at the wide angle end, FIG. 26B shows the intermediate state, and FIG. 26C shows the state at the telephoto end;

FIG. 27 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fourteenth embodiment of the present invention;

FIG. 28A, FIG. 28B, and FIG. 28C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fourteenth embodiment, where, FIG. 28A shows the state at the wide angle end, FIG. 28B shows the intermediate state, and FIG. 28C shows the state at the telephoto end;

FIG. 29 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fifteenth embodiment of the present invention;

FIG. 30A, FIG. 30B, and FIG. 30C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fifteenth embodiment, where, FIG. 30A shows the state at the wide angle end, FIG. 30B shows the intermediate state, and FIG. 30C shows the state at the telephoto end;

FIG. 31 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a sixteenth embodiment of the present invention;

FIG. 32A, FIG. 32B, and FIG. 32C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the sixteenth embodiment, where, FIG. 32A shows the state at the wide angle end, FIG. 32B shows the intermediate state, and FIG. 32C shows the state at the telephoto end;

FIG. 33 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a seventeenth embodiment of the present invention;

FIG. 34A, FIG. 34B, and FIG. 34C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the seventeenth embodiment, where, FIG. 34A shows the state at the wide angle end, FIG. 34B shows the intermediate state, and FIG. 34C shows the state at the telephoto end;

FIG. 35 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eighteenth embodiment of the present invention;

FIG. 36A, FIG. 36B, and FIG. 36C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eighteenth embodiment, where, FIG. 36A shows the state at the wide angle end, FIG. 36B shows the intermediate state, and FIG. 36C shows the state at the telephoto end;

FIG. 37 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a nineteenth embodiment of the present invention;

FIG. 38A, FIG. 38B, and FIG. 38C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the nineteenth embodiment, where, FIG. 38A shows the state at the wide angle end, FIG. 38B shows the intermediate state, and FIG. 38C shows the state at the telephoto end;

FIG. 39 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twentieth embodiment of the present invention;

FIG. 40A, FIG. 40B, and FIG. 40C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twentieth embodiment, where, FIG. 40A shows the state at the wide angle end, FIG. 40B shows the intermediate state, and FIG. 40C shows the state at the telephoto end;

FIG. 41 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty first embodiment of the present invention;

FIG. 42A, FIG. 42B, and FIG. 42C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty first embodiment, where, FIG. 42A shows the state at the wide angle end, FIG. 42B shows the intermediate state, and FIG. 42C shows the state at the telephoto end;

FIG. 43 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty second embodiment of the present invention;

FIG. 44A, FIG. 44B, and FIG. 44C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty second embodiment, where, FIG. 44A shows the state at the wide angle end, FIG. 44B shows the intermediate state, and FIG. 44C shows the state at the telephoto end;

FIG. 45 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty third embodiment of the present invention;

FIG. 46A, FIG. 46B, and FIG. 46C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty third embodiment, where, FIG. 46A shows the state at the wide angle end, FIG. 46B shows the intermediate state, and FIG. 46C shows the state at the telephoto end;

FIG. 47 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty fourth embodiment of the present invention;

FIG. 48A, FIG. 48B, and FIG. 48C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty fourth embodiment, where, FIG. 48A shows the state at the wide angle end, FIG. 48B shows the intermediate state, and FIG. 48C shows the state at the telephoto end;

FIG. 49 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty fifth embodiment of the present invention;

FIG. 50A, FIG. 50B, and FIG. 50C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty fifth embodiment, where, FIG. 50A shows the state at the wide angle end, FIG. 50B shows the intermediate state, and FIG. 50C shows the state at the telephoto end;

FIG. 51 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty sixth embodiment of the present invention;

FIG. 52A, FIG. 52B, and FIG. 52C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty sixth embodiment, where, FIG. 52A shows the state at the wide angle end, FIG. 52B shows the intermediate state, and FIG. 52C shows the state at the telephoto end;

FIG. 53 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty seventh embodiment of the present invention;

FIG. 54A, FIG. 54B, and FIG. 54C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty seventh embodiment, where, FIG. 54A shows the state at the wide angle end, FIG. 54B shows the intermediate state, and FIG. 54C shows the state at the telephoto end;

FIG. 55 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty eighth embodiment of the present invention;

FIG. 56A, FIG. 56B, and FIG. 56C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty eighth embodiment, where, FIG. 56A shows the state at the wide angle end, FIG. 56B shows the intermediate state, and FIG. 56C shows the state at the telephoto end;

FIG. 57 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty ninth embodiment of the present invention;

FIG. 58A, FIG. 58B, and FIG. 58C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty ninth embodiment, where, FIG. 58A shows the state at the wide angle end, FIG. 58B shows the intermediate state, and FIG. 58C shows the state at the telephoto end;

FIG. 59 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirtieth embodiment of the present invention;

FIG. 60A, FIG. 60B, and FIG. 60C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirtieth embodiment, where, FIG. 60A shows the state at the wide angle end, FIG. 60B shows the intermediate state, and FIG. 60C shows the state at the telephoto end;

FIG. 61 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty first embodiment of the present invention;

FIG. 62A, FIG. 62B, and FIG. 62C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty first embodiment, where, FIG. 62A shows the state at the wide angle end, FIG. 62B shows the intermediate state, and FIG. 62C shows the state at the telephoto end;

FIG. 63 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty second embodiment of the present invention;

FIG. 64A, FIG. 64B, and FIG. 64C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty second embodiment, where, FIG. 64A shows the state at the wide angle end, FIG. 64B shows the intermediate state, and FIG. 64C shows the state at the telephoto end;

FIG. 65 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty third embodiment of the present invention;

FIG. 66A, FIG. 66B, and FIG. 66C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty third embodiment, where, FIG. 66A shows the state at the wide angle end, FIG. 66B shows the intermediate state, and FIG. 66C shows the state at the telephoto end;

FIG. 67 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty fourth embodiment of the present invention;

FIG. 68A, FIG. 68B, and FIG. 68C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty fourth embodiment, where, FIG. 68A shows the state at the wide angle end, FIG. 68B shows the intermediate state, and FIG. 68C shows the state at the telephoto end;

FIG. 69 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty fifth embodiment of the present invention;

FIG. 70A, FIG. 70B, and FIG. 70C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty fifth embodiment, where, FIG. 70A shows the state at the wide angle end, FIG. 70B shows the intermediate state, and FIG. 70C shows the state at the telephoto end;

FIG. 71 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty sixth embodiment of the present invention;

FIG. 72A, FIG. 72B, and FIG. 72C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty sixth embodiment, where, FIG. 72A shows the state at the wide angle end, FIG. 72B shows the intermediate state, and FIG. 72C shows the state at the telephoto end;

FIG. 73 is a cross-sectional view along the optical axis showing an optical arrangement at the wide angle end of a zoom lens according to a thirty seventh embodiment of the present invention;

FIG. 74A, FIG. 74B, and FIG. 74C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty seventh embodiment, where, FIG. 74A shows the state at the wide angle end, FIG. 74B shows the intermediate state, and FIG. 74C shows the state at the telephoto end;

FIG. 75 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty eighth embodiment of the present invention;

FIG. 76A, FIG. 76B, and FIG. 76C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty eighth embodiment, where, FIG. 76A shows the state at the wide angle end, FIG. 76B shows the intermediate state, and FIG. 76C shows the state at the telephoto end;

FIG. 77 is a frontward perspective view showing an appearance of a digital camera 40 in which, a zoom optical system according to the present invention is incorporated;

FIG. 78 is a rearward perspective view of the digital camera 40;

FIG. 79 is a cross-sectional view showing an optical arrangement of the digital camera 40;

FIG. 80 is a frontward perspective view of a personal computer 300 with its cover opened, which is an example of an information processing apparatus in which, the zoom optical system of the present invention is built-in as an objective optical system;

FIG. 81 is a cross-sectional view of a photographic optical system 303 of the personal computer 300;

FIG. 82 is a side view of the personal computer 300; and

FIG. 83A, FIG. 83B, and FIG. 83C are diagrams showing a portable telephone which is an example of the information processing apparatus in which, the zoom optical system of the present invention is built-in as the taking optical system, where, FIG. 83A is a front view of a portable telephone 400, FIG. 83B is a side view of the portable telephone 400, and FIG. 83C is a cross-sectional view of a taking optical system 405.

BEST MODE FOR CARRYING OUT THE INVENTION

Prior to a description of embodiments, an action and an effect of the present invention will be described below.

An image forming optical system of the present invention, where the image forming optical system includes a positive lens group, a negative lens group, and an aperture stop, has a basic structure in which the negative lens group is disposed at an object side of the aperture stop, and the negative lens group includes a cemented lens which is formed by cementing a plurality of lenses.

In this manner, in the basic structure, since the cemented lens is used in the negative lens group which is at the object side of the aperture stop, a change in a chromatic aberration of magnification in a zoom lens, at the time of zooming, is easily suppressed. Moreover, with a fewer number of lenses, it is possible to suppress sufficiently an occurrence of color spreading over a zoom range. Moreover, although it is effective to enhance a refracting power of the lens group for making small the entire optical system, in this basic structure, since the refracting power can be easily imparted without making thick as far as possible, the negative lens group (the negative lens group on the object side of the aperture stop) of which the refractive index is to be made strong, it is easy to make small the entire optical system.

Further, in the abovementioned basic structure, it is preferable that at least one lens forming the cemented lens has the following characteristics. In other words, in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set, it is desirable that Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and an area determined by following conditional expressions (2a) and (3a). 1.45<β<2.15  (1a) 1.30<Nd<2.20  (2a) 3<νd<12  (3a)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.

Here, a glass means a lens material such as a glass and a resin. Moreover, as a cemented lens, a lens in which a plurality of lenses made of a glass selected appropriately is cemented, is used.

When a value is lower than the lower limit value in the conditional expression (1a), since a refractive index is low, an effect when an aspheric surface is provided on a side which is in contact with air is small, and a correction of a spherical aberration, a coma aberration, and a distortion becomes difficult. Or, since the Abbe's number is low, a correction of a chromatic aberration, as an extremely thin cemented lens is possible, but when the side in contact with air is made to be an aspheric surface, a chromatic coma and a chromatic aberration of magnification of high order are susceptible to occur, and a degree of freedom of an aberration correction is decreased.

When a value is higher than an upper limit value in the conditional expression (1a), since a power and a thickness of the cemented lens is required to be more than a certain magnitude for the correction of the chromatic aberration, it becomes susceptible to be effected by optical characteristics which depend on an environment of the material.

When a value is lower than a lower limit value in the conditional expression (2a), the effect when the aspheric surface is provided on the side which is in contact with air is small, and the correction of the spherical aberration, the coma aberration, and the distortion becomes difficult.

When a value is higher than an upper limit value in the conditional expression (2a), in a case of a material which includes organic properties, when the refractive index is excessively high, a temperature variance becomes excessively high, and optical characteristics which depend on the environment are susceptible to become unstable. Moreover, a reflectivity becomes excessively high, and a ghost is susceptible to occur even when coating is optimized.

When a value is lower than a lower limit value in the conditional expression (3a), the correction of the chromatic aberration, as an extremely thin cemented lens is possible, but when the side in contact with air is made to be an aspheric surface, the chromatic coma and the chromatic aberration of magnification of high order are susceptible to occur, and the degree of freedom of the aberration correction is decreased.

When a value is higher than an upper limit value in the conditional expression (3a), it is necessary to enhance a refracting power of the cemented lens for correcting the chromatic aberration, and it is advantageous for a correction of a Petzval's sum, but it becomes susceptible to be effected by the optical characteristics which depend on the environment of the material.

It is more preferable when a following conditional expression (1a′) is satisfied. 1.48<β<2.04  (1a′)

Furthermore, it is even more preferable when a following conditional expression (1a″) is satisfied. 1.50<β<2.00  (1a″)

Moreover, it is more preferable when a following conditional expression (2a′) is satisfied. 1.58<Nd<2.10  (2a′)

Furthermore, it is more preferable when a following conditional expression (2a″) is satisfied. 1.63<Nd<1.95  (2a″)

Moreover, it is more preferable when a following conditional expression (3a′) is satisfied. 5<νd<10  (3a′)

Furthermore, it is more preferable when a following conditional expression (3a″) is satisfied. 6<νd<9  (3a″)

Or, in the abovementioned basic structure, it is preferable that at least one lens forming the cemented lens has the following characteristics. In other words, in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=×νd+β (where, α=−0.017) is set, it is desirable that Nd and νd of at least one lens forming the cemented lens is included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1b), and a line when an upper limit value is in a range of the following conditional expression (1b), and an area determined by following conditional expressions (2b) and (3b). 1.45<p<2.15  (1b) 1.58<Nd<2.20  (2b) 3<νd<40  (3b)

Here, Nd denotes the refractive index, and νd denotes the Abbe's number.

When a value is lower than a lower limit value in the conditional expression (1b), since the refractive index is low, the effect when the aspheric surface is provided on the side which is in contact with air is small, and the correction of the spherical aberration, the coma aberration, and the distortion becomes difficult. Or, since the Abbe's number is low, the correction of the chromatic aberration, as an extremely thin cemented lens is possible, but when the side in contact with air is made to be an aspheric surface, the chromatic coma, and the chromatic aberration of magnification of high order are susceptible to occur, and the degree of freedom of the aberration correction is decreased.

When a value is higher than an upper limit value in the conditional expression (1b), a correction level of the chromatic aberration and the Petzval's sum become same as of a general optical glass lens, and characteristics of the present invention are not achieved.

When a value is lower than a lower limit value in the conditional expression (2b), the effect when the aspheric surface is provided on the side which is in contact with air is small, and the correction of the spherical aberration, the coma aberration, and the distortion becomes difficult.

When a value is higher than an upper limit value in the conditional expression (2b), in the case of a material which includes organic properties, when the refractive index is excessively high, the temperature variance becomes excessively high, and the optical characteristics which depend on the environment are susceptible to become unstable. Moreover, the reflectivity becomes excessively high, and a ghost is susceptible to occur even when the coating is optimized.

When a value is lower than a lower limit value in the conditional expression (3b), the correction of the chromatic aberration, as an extremely thin cemented lens is possible, but when the side in contact with air is made to be an aspheric surface, the chromatic coma and the chromatic aberration of magnification of high order are susceptible to occur, and the degree of freedom of the aberration correction is decreased.

When a value is higher than an upper limit value in the conditional expression (3b), it is necessary to enhance the refracting power of the cemented lens for correcting the chromatic aberration, and it is advantageous for the correction of the Petzval's sum, but it becomes susceptible to be effected by the optical characteristics which depend on the environment of the material.

It is more preferable when a following conditional expression (1b′) is satisfied. 1.48<β<2.04  (1b′)

Furthermore, it is even more preferable when a following conditional expression (1b″) is satisfied. 1.50<β<2.00  (1b″)

Moreover, it is more preferable when a following conditional expression (2b′) is satisfied. 1.60<Nd<2.10  (2b′)

Furthermore, it is more preferable when a following conditional expression (2b″) is satisfied. 1.63<Nd<1.95  (2b″)

Moreover, it is more preferable when a following conditional expression (3b′) is satisfied. 5<νd<30  (3b′)

Furthermore, it is more preferable when a following conditional expression (3b″) is satisfied. 6<νd<25  (3b″)

Moreover, it is preferable that the cemented lens is formed by a lens (hereinafter, called as a ‘predetermined lens’) having the values of Nd and νd which are included in both the areas mentioned above, and a lens other than the predetermined lens, and a center thickness along an optical axis of the predetermined lens is less than a center thickness along an optical axis of the other lens. By making such an arrangement, it is possible to realize a more favorable correction of each aberration mentioned above, and thinning of the lens group.

Moreover, the cemented lens may be a compound lens which is formed by closely adhering and hardening a resin on a lens surface (lens surface of the other lens), in order to improve a manufacturing accuracy. Here, the resin which is adhered closely and hardened corresponds to the predetermined lens.

Moreover, the cemented lens may be a compound lens which is formed by closely adhering and hardening a glass on the lens surface (lens surface of the other lens), as it is advantageous for resistance such as a light resistance and a chemical resistance. Here, the glass which is adhered closely and hardened corresponds to the predetermined lens.

Furthermore, in the cemented lens, a center thickness t1 along the optical axis of the predetermined lens (one lens in which Nd and νd are included in both the areas mentioned above) may satisfy a following conditional expression (4), in order to make a size small and to carry out molding stably. 0.22<t1<2.0  (4)

It is more preferable that a following conditional expression (4′) is satisfied. 0.3<t1<1.5  (4′)

Furthermore, it is even more preferable that a following conditional expression (4″) is satisfied. 0.32<t1<1.0  (4″)

Moreover, the image forming optical system may be a zoom lens of which, a group on the closest side of an object is a positive lens group, from a viewpoint of having a high, magnification of the zoom and an improvement in a brightness of the lens.

Moreover, the image forming optical system may be a zoom lens of which, a group on the closest side of an object is a negative lens group, for making the size small.

Moreover, the image forming optical system may have a prism for folding, for facilitating thinning of an optical system with respect to a direction of taking a photo.

Moreover, in the image forming optical system, the prism may be in a group on the closest side of an object, for further facilitating thinning.

Incidentally, when a pixel size of the electronic image pickup element becomes smaller than a certain size, a component of a frequency higher than a Nyquist frequency is eliminated due to an effect of diffraction. Therefore, when this is used, it is possible to omit an optical low-pass filter. This is preferable from a point of making the entire optical system as thin as possible.

For this, it is preferable that a following conditional expression (6) is satisfied. Fw≧a(μm)  (6)

where, Fw is a full-aperture F value, and a is a distance between pixels (unit: μm) in a horizontal direction of the electronic image pickup element.

When the conditional expression (6) is satisfied, the optical low-pass filter is not required to be disposed in an optical path. Accordingly, it is possible to make the optical system small.

In a case of satisfying the conditional expression (6), it is preferable that the aperture stop is let to be open only. This means that the optical system in this case is an optical system with a constant diameter of the aperture stop all the time. Moreover, in the optical system in this case, since an operation of narrowing is not necessary, it is possible to omit a narrowing mechanism. Accordingly, the size can be made small saving that much space. When the conditional expression (6) is not satisfied, the optical low-pass filter is necessary.

Moreover, it is more preferable that a conditional expression (6′) is satisfied. Fw≧1.2a(μm)  (6′)

Furthermore, it is even more preferable that a conditional expression (6″) is satisfied. Fw≧1.4a(μm)  (6″)

Finally, an electronic image pickup apparatus will be described below. As the electronic image pickup apparatus, an electronic image pickup apparatus in which, both a thinning of depth and a widening of image angle are realized is preferable.

Here, it is assumed that an infinite object is imaged by an optical system which has no distortion. In this case, since the image which is formed has no distortion, f=y/tan ω holds.

Here, y is a height of an image point from an optical axis, f is a focal length of the image forming system, and ω is an angle with respect to an optical axis in a direction of an object point corresponding to the image point connecting from a center on an image pickup surface, up to a position of y.

On the other hand, when the optical system has a barrel distortion, f>y/tan ω holds. In other words, when f and y are let to be constant values, ω becomes a substantial value.

Therefore, in the electronic image pickup apparatus, it is preferable to use a zoom lens as the image forming optical system. As a zoom lens, particularly in a focal length near a wide angle end, an optical system having a substantial barrel distortion may be used intentionally. In this case, since a purpose is served without correcting the distortion, it is possible to achieve the widening of the image angle of the optical system. However, an image of the object is formed on the electronic image pickup element, in a state of having the barrel distortion. Therefore, in the electronic image pickup apparatus, image data obtained by the electronic image pickup element is processed by an image processing. In this process, the image data (a shape of the image data) is changed such that the barrel distortion is corrected. By changing the image data, image data which is obtained finally, takes a shape almost similar to the object. Accordingly, based on this image data, the image of the object may be output to a CRT or a printer.

Here, as the image forming optical system (zoom lens), an image forming optical system which satisfies a following conditional expression (7) at the time of infinite object point focusing may be adopted. 0.7<y ₀₇/(fw·tan ω_(07w))<0.96  (7)

where, y₀₇ is indicated as y₀₇=0.7y₁₀ when, in an effective image pickup plane (plane in which image pickup is possible), a distance from a center up to a farthest point (maximum image height) is let to be y₁₀. Moreover, ω_(07w) is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface in a wide angle end, up to a position of y₀₇.

The conditional expression (7) mentioned above is an expression in which, a degree of the barrel distortion in a zoom wide angle end is regulated. When the conditional expression (7) is satisfied, it is possible to fetch information of the wide image angle without making the optical system enlarged. An image which is distorted to barrel shape is subjected to photoelectric conversion, and becomes image data which is distorted to barrel shape. However, on the image data which is distorted to the barrel shape, a process equivalent to a shape change of the image is carried out electrically by the image processing means which is a signal processing system of the electronic image pickup apparatus. When this process is carried out, even when the image data output from the image processing means is reproduced finally by a display apparatus, the distortion is corrected, and an image almost similar to a shape of an object to be photographed is obtained.

Here, when a value is higher than an upper limit value in the conditional expression (7), particularly, when a value close to 1 is to be taken, it is possible to carry out by the image processing means, a correction equivalent to a correction in which, the distortion is corrected favorably optically, but it is difficult to fetch an image over a wide angle of visibility. On the other hand, when a value is lower than a lower limit value in the conditional expression (7), a rate of enlarging in a direction of radiating in a portion around an image angle when the image distortion due to the distortion of the optical system is corrected by the image processing means, becomes excessively high. As a result of this, a deterioration in a sharpness of the area around the image becomes remarkable.

On the other hand, by satisfying the conditional expression (7), it is possible to widen the angle (make an angle in a vertical direction in the distortion to be 38° or more) and to make small the optical system.

Moreover, it is more preferable when a following conditional expression (7′) is satisfied. 0.75<y ₀₇/(fw·tan ω_(07w))<0.94  (7′)

Furthermore, it is even more preferable when a following conditional expression (7″) is satisfied. 0.80<y ₀₇/(fw·tan ω_(07w))<0.92  (7″)

The image forming optical system of the present invention, even when an electronic image pickup element of a large number of pixels is used, is capable of achieving thinning and reduction in size of a volume of the image forming optical system, by satisfying or providing each of conditional expressional and structural characteristics mentioned above, and realizing a favorable correction of aberration. Moreover, the image forming optical system of the present invention is capable of providing (satisfying) in combination the conditional expressional and structural characteristics mentioned above. In this case, it is possible to achieve further reduction in size and thinning, or the favorable aberration correction. Moreover, in the electronic image pickup apparatus having the image forming optical system of the present invention, it is possible to achieve the thinning and reduction in size of the volume of the image forming optical system, and further, to have both of the favorable correction of various aberrations, and widening of the angle.

Embodiments of the present invention will be described below by using the accompanying diagrams.

As a zoom lens of the present invention, a five-group structure or a four-group structure can be taken into consideration. In a zoom lens of the five-group structure, it is preferable to dispose from an object side, each lens group in order of a first lens group having a positive refracting power, a second lens group having a negative refracting power, a third lens group having a positive refracting power, a fourth lens group having a negative refracting power, and a fifth lens group having a positive refracting power.

Here, it is preferable that the first lens group includes a negative lens, a prism, and a positive lens. At this time, it is more preferable to dispose these in order of the negative lens, the prism, and the positive lens, from the object side. Moreover, the first lens group may include only one negative lens, one prism, and one positive lens.

Moreover, it is preferable that the second lens group includes a cemented lens and a positive lens. At this time, it is more preferable to dispose the positive lens on an image side of the cemented lens. Moreover, it is preferable to form the cemented lens by a positive lens and a negative lens, and to dispose the cemented lens such that the negative lens is positioned at the image side. Or, it is preferable to form the second lens group by a negative lens, and to dispose the cemented lens such that the negative lens having a thin center-thickness is positioned at the object side. The second lens group may include only one cemented lens and one positive lens. In this case, the cemented lens is formed by one positive lens and one negative lens, or two negative lenses.

Moreover, it is preferable that the third lens group includes a positive lens and a negative lens. At this time, it is more preferable to form a cemented lens by the positive lens and the negative lens, and to dispose the cemented lens such that the positive lens is positioned at the object side. The third lens group may be formed by only one cemented lens. In this case, the cemented lens is formed by one positive lens and one negative lens.

Moreover, it is preferable that the fourth lens group includes a negative lens. At this time, it is preferable to form the fourth lens group by only one negative lens.

Moreover, it is preferable that the fifth lens group includes a positive lens. At this time, it is preferable to form the fifth lens group by only one positive lens.

Moreover, in a zoom lens of the four-group structure, it is preferable to dispose each lens group in order of a first lens group having a negative refracting power, a second lens group having a positive refracting power, a third lens group having a negative refracting power, and a fourth lens group having a positive refracting power, from the object side.

Here, it is preferable that the first lens group-includes a prism and at least two cemented lenses. At this time, it is more preferable to dispose these in order of one cemented lens, the prism, and the other cemented lens, from the object side. Moreover, it is preferable to form the one cemented lens by a positive lens and a negative lens, and to dispose the one cemented lens such that the negative lens is positioned at the object side. Or, the one cemented lens may be formed by only a negative lens, and may be disposed such that the negative lens having thin center-thickness is positioned at the object side.

Moreover, it is preferable to form the other cemented lens by a positive lens and a negative lens, and to dispose the other cemented lens such that the positive lens is positioned at the object side. Or, the other cemented lens may be formed by only a negative lens.

The first lens group may include only one prism and two cemented lenses. In this case, the cemented lens is formed by one positive lens and one negative lens, or by two negative lenses.

Moreover, it is preferable that the second lens group includes a positive lens and a negative lens. At this time, it is more preferable to form a cemented lens by a positive lens and a negative lens, and to dispose the cemented lens such that the positive lens is positioned at the object side. The second lens group may be formed by only one cemented lens. In this case, the cemented lens is formed by one positive lens and one negative lens.

Moreover, it is preferable that the third lens group includes a positive lens and a negative lens, or a negative lens. At this time, it is more preferable to form a cemented lens by a positive lens and a negative lens, and to dispose the cemented lens such that the negative lens is positioned at the object side. Or, the cemented lens may be formed by two negative lenses. The third lens group may include only one cemented lens. In this case, the cemented lens is formed by one positive lens and one negative lens, or two negative lenses.

Moreover, it is preferable that the fourth lens group includes a positive lens and a negative lens. At this time, it is preferable to form a cemented lens by a positive lens and a negative lens, and to dispose the cemented lens such that the positive lens is positioned at the object side. The fourth lens group may be formed by only one cemented lens. In this case, the cemented lens includes one positive lens and one negative lens.

It is possible to distribute a refracting power of one lens into two lenses. Accordingly, in each of the lens groups mentioned above, it is possible to substitute one lens by two lenses. However, from a point of view of the reduction in size and thinning, it is preferable to let the number of lenses to be substituted by two lenses in each lens group, to be only one.

First Embodiment

FIG. 1 is a cross-sectional view along an optical axis showing an optical arrangement at the time of an infinite object point focusing at a wide angle end of a zoom lens according to a first embodiment;

FIG. 2A, FIG. 2B, and FIG. 2C are diagrams showing a spherical aberration, an astigmatism, a distortion, and a chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the first embodiment, where, FIG. 2A shows a state at the wide angle end, FIG. 2B shows an intermediate state, and FIG. 2C shows a state at a telephoto end.

The zoom lens of the first embodiment, as shown in FIG. 1, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagrams, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a positive meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a positive meniscus lens L123 having a convex surface directed toward the object side, and has a negative refracting power as a whole. The positive meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132 and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface toward the object side, of the biconvex lens L113 in the first lens group G1, a surface toward the object side of the positive meniscus lens L121 having the convex surface directed toward the image side, and a surface toward the image side of the biconvex lens L122 in the second lens group G2, a surface toward the object side of the biconvex lens L131, and a surface toward the image side of the biconcave lens L132 in the third lens group G3, and a surface toward the object side of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.

Next, numerical data of optical members forming the zoom lens of the first embodiment will be enumerated.

In the numerical data of the first embodiment, r1, r2, . . . denote a radius of curvature of each lens surface; d1, d2, . . . denote a thickness or an air space of each lens; nd1, nd2, . . . denote a refractive index at line d of each lens; νd1, νd2, denote the Abbe's number for each lens; Fno. denotes an F number; f denotes a focal length of an overall system; and D0 denotes a distance from the object to the first surface.

An aspheric surface shape is expressed by a following expression when a direction of an optical axis is let to be z, a direction orthogonal to the optical axis is let to be y, a conical coefficient is let to be K, and an aspheric coefficient is let to be A4, A6, A8, and A10. z=(y ² /r)/[1+{1−(1+K)(y/r)²}^(1/2) ]+A4y ⁴ +A6y ⁶ +A8y ⁸ +A10y ¹⁰

Moreover, E denotes a power of 10. These symbols of data values are common even in numerical data of embodiments which will be described later. The conical coefficient might also be denoted by k.

Next, numerical data of the first embodiment will be enumerated.

Numerical data 1 r1 = 25.36 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.004 d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 33.927 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −27.177 d6 = D6 r7 = −461.447 d7 = 0.1 Nd7 = 1.41244 νd7 = 12.42 (Aspheric surface) r8 = −92.289 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 6.012 d9 = 0.7 (Aspheric surface) r10 = 8.081 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = 63.91 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.812 d13 = 5.49 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −11.451 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 33.504 d15 = D15 (Aspheric surface) r16 = 26.9 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.047 d17 = D17 r18 = 9.921 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = 236.372 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients 5th surface k = 0 A4 = 1.21460E−05 A6 = 2.15403E−07 A8 = 0 7th surface k = 0 A4 = −6.49637E−04 A6 = 4.67785E−05 A8 = −1.11723E−06 9th surface k = 0 A4 = −7.36988E−04 A6 = 3.10428E−05 A8 = −1.20842E−06 13th surface k = 0 A4 = 1.33646E−04 A6 = 1.99909E−06 A8 = 8.19731E−08 15th surface k = 0 A4 = 7.65187E−04 A6 = 4.66680E−06 A8 = 1.27977E−06 18th surface k = 0 A4 = −7.77242E−05 A6 = 8.66914E−06 A8 = −2.36765E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.005 13.699 17.993 FNO. 2.88 4.93 6.03 D6 0.8 7.08 8.33 D11 8.92 2.64 1.38 D12 11.78 4.21 1.19 D15 1.21 12.51 14.59 D17 1.92 2.3 3.68 D19 5.08 0.96 0.51 D23 1.36 1.36 1.36

Second Embodiment

FIG. 3 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a second embodiment of the present invention.

FIG. 4A, FIG. 4B, and FIG. 4C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the second embodiment, where, FIG. 4A shows the state at the wide angle end, FIG. 4B shows the intermediate state, and FIG. 4C shows the state at the telephoto end.

The zoom lens of the second embodiment, as shown in FIG. 2, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a positive meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a positive meniscus lens L123 having a convex surface directed toward the object side, and has a negative refracting power as a whole. The positive meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the positive meniscus lens L121 having the convex surface directed toward the image side, and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.

Next, numerical data of the second embodiment will be enumerated.

Numerical data 2 r1 = 24.594 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.001 d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 36.646 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −28.175 d6 = D6 r7 = −412.042 d7 = 0.1 Nd7 = 1.42001 νd7 = 6.55 (Aspheric surface) r8 = −82.408 d8 = 0.7 Nd8 = 1.804 νd8 = 46.57 r9 = 5.748 d9 = 0.7 (Aspheric surface) r10 = 7.508 d10 = 2.2 Nd10 = 1.762 νd10 = 40.1 r11 = 49.209 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.579 d13 = 5.88 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −12.379 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 33.143 d15 = D15 (Aspheric surface) r16 = 75.485 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.793 d17 = D17 r18 = 9.468 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = 110.758 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients 5th surface k = 0 A4 = 1.75267E−05 A6 = 3.00970E−07 A8 = 0 7th surface k = 0 A4 = 8.41987E−05 A6 = 2.81257E−06 A8 = −4.40220E−07 9th surface k = 0 A4 = −3.40594E−04 A6 = 1.28078E−05 A8 = −1.47015E−06 13th surface k = 0 A4 = 9.29393E−05 A6 = 2.27583E−06 A8 = 2.74322E−08 15th surface k = 0 A4 = 8.13829E−04 A6 = 7.34253E−06 A8 = 1.33131E−06 18th surface k = 0 A4 = −8.92455E−05 A6 = 6.36509E−06 A8 = −1.97541E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.004 13.7 17.996 FNO. 2.88 4.93 6.03 D6 0.8 7.2 8.34 D11 8.93 2.53 1.39 D12 11.51 4.24 1.2 D15 1.2 11.76 14.36 D17 1.55 2.58 3.35 D19 5.15 0.83 0.5 D23 1.36 1.36 1.36

Third Embodiment

FIG. 5 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a third embodiment of the present invention.

FIG. 6A, FIG. 6B and FIG. 6C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the third embodiment, where, FIG. 6A shows the state at the wide angle end, FIG. 6B shows the intermediate state, and FIG. 6C shows the state at the telephoto end.

The zoom lens of the third embodiment, as shown in FIG. 5, has in order from the object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a positive meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a positive meniscus lens L123 having a convex surface directed toward the image side, and has a negative refracting power as a whole. The positive meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, a surface toward the object side of the positive meniscus lens L121 having the convex surface directed toward the image side, and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the third embodiment will be enumerated.

Numerical data 3 r1 = 26.034 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.008 d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 31.427 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −28.242 d6 = D6 r7 = −450.644 d7 = 0.1 Nd7 = 1.51824 νd7 = 12.85 (Aspheric surface) r8 = −90.128 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 6.379 d9 = 0.7 (Aspheric surface) r10 = 8.418 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = 53.205 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.744 d13 = 5.68 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −11.578 d14 = 1 Nd14 = 1.84666 vd14 = 23.78 r15 = 29.590 d15 = D15 (Aspheric surface) r16 = 50.592 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.911 d17 = D17 r18 = 10.239 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −99.931 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 = 1.17810E−05 A6 = 1.82657E−07 A8 = 0  7th surface k = 0 A4 = −4.42069E−04 A6 = 3.26119E−05 A8 = −6.84627E−07  9th surface k = 0 A4 = −6.04325E−04 A6 = 2.50939E−05 A8 = −7.15313E−07 13th surface k = 0 A4 = 1.11989E−04 A6 = 2.08910E−06 A8 = 6.26649E−08 15th surface k = 0 A4 = 7.60266E−04 A6 = 7.40588E−06 A8 = 1.27917E−06 18th surface k = 0 A4 = −1.02638E−04 A6 = 9.54050E−06 A8 = −2.57130E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.005 13.699 17.987 FNO. 2.88 4.93 6.03 D6 0.8 6.95 8.31 D11 8.88 2.73 1.37 D12 11.72 4.04 1.18 D15 1.21 12.15 14.34 D17 1.63 2.17 3.45 D19 4.93 1.12 0.52 D23 1.36 1.36 1.36

Fourth Embodiment

FIG. 7 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fourth embodiment of the present invention.

FIG. 8A, FIG. 8B, and FIG. 8C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fourth embodiment, where, FIG. 8A shows the state at the wide angle end, FIG. 8B shows the intermediate state, and FIG. 8C shows the state at the telephoto end.

The zoom lens of the fourth embodiment, as shown in FIG. 7, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a positive meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a positive meniscus lens L123 having a convex surface directed toward the object side, and has a negative refracting power as a whole. The positive meniscus lens L121 having the convex surface directed toward the object side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the positive meniscus lens L121 having the convex surface directed toward the image side and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the fourth embodiment will be enumerated.

Numerical data 4 r1 = 26.322 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.013 d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 29.452 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −27.694 d6 = D6 r7 = −531.522 d7 = 0.1 Nd7 = 1.54856 νd7 = 7.04 (Aspheric surface) r8 = −106.303 d8 = 0.7 Nd8 = 1.801 νd8 = 34.97 r9 = 5.870 d9 = 0.7 (Aspheric surface) r10 = 7.8 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = 53.964 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.924 d13 = 5.76 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −12.116 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 29.891 d15 = D15 (Aspheric surface) r16 = 39.978 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.323 d17 = D17 r18 = 9.450 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −189.465 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 = 9.75478E−06 A6 = 1.51579E−07 A8 = 0  7th surface k = 0 A4 = −1.95112E−04 A6 = 1.43936E−05 A8 = −2.98225E−07  9th surface k = 0 A4 = −5.10533E−04 A6 = 1.21310E−05 A8 = −6.59060E−07 13th surface k = 0 A4 = 1.12806E−04 A6 = 1.80736E−06 A8 = 4.78959E−08 15th surface k = 0 A4 = 7.17631E−04 A6 = 7.87011E−06 A8 = 9.76118E−07 18th surface k = 0 A4 = −9.54875E−05 A6 = 7.46371E−06 A8 = −2.00942E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 5.995 13.694 17.985 FNO. 2.86 4.93 6.05 D6 0.79 6.91 8.34 D11 8.92 2.81 1.37 D12 11.67 3.89 1.18 D15 1.21 12.04 14.24 D17 1.53 2.07 3.35 D19 4.89 1.29 0.52 D23 1.36 1.37 1.37

Fifth Embodiment

FIG. 9 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fifth embodiment of the present invention.

FIG. 10A, FIG. 10B, and FIG. 10C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fifth embodiment, where, FIG. 10A shows the state at the wide angle end, FIG. 10B shows the intermediate state, and FIG. 10C shows the state at the telephoto end.

The zoom lens of the fifth embodiment, as shown in FIG. 9, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a positive meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a positive meniscus lens L123 having a convex surface directed toward the object side, and has a negative refracting power as a whole. The positive meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the positive meniscus lens L121 having the convex surface directed toward the image side, and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the fifth embodiment will be enumerated.

Numerical data 5 r1 = 22.06 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 8.728 d2 = 3.48 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 30.986 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −27.99 d6 = D6 r7 = −115.268 d7 = 0.1 Nd7 = 1.65228 νd7 = 12.75 (Aspheric surface) r8 = −126.689 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 5.968 d9 = 0.7 (Aspheric surface) r10 = 8.311 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = 176.709 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.790 d13 = 6.26 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −11.462 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 28.003 d15 = D15 (Aspheric surface) r16 = 15.819 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 8.139 d17 = D17 r18 = 11.145 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −741.85 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 = 2.56867E−05 A6 = 2.52676E−07 A8 = 0  7th surface k = 0 A4 = −1.22696E−04 A6 = 8.55567E−06 A8 = −7.67236E−08  9th surface k = 0 A4 = −5.12267E−04 A6 = 4.37980E−06 A8 = −3.04805E−07 13th surface k = 0 A4 = 6.62474E−05 A6 = 1.59411E−06 A8 = 2.28358E−08 15th surface k = 0 A4 = 6.81156E−04 A6 = 1.15567E−05 A8 = 8.59263E−07 18th surface k = 0 A4 = −5.99348E−05 A6 = 9.65602E−06 A8 = −1.88588E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.42 17.995 FNO. 3.27 5.28 6.49 D6 1.53 8.13 9.28 D11 11.01 2.98 0.41 D12 7.5 2.21 0.4 D15 0.9 11.71 14.54 D17 1.54 2.08 3.46 D19 4.85 1.27 0.39 D23 1.36 1.36 1.36

Sixth Embodiment

FIG. 11 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a sixth embodiment of the present invention.

FIG. 12A, FIG. 12B, and FIG. 12C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the sixth embodiment, where, FIG. 12A shows the state at the wide angle end, FIG. 12B shows the intermediate state, and FIG. 12C shows the state at the telephoto end.

The zoom lens of the sixth embodiment, as shown in FIG. 11, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a negative meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a biconvex lens L123, and has a negative refracting power as a whole. The negative meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142 and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the negative meniscus lens L121 having the convex surface directed toward the image side and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the sixth embodiment will be enumerated.

Numerical data 6 r1 = 22.209 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 8.697 d2 = 3.18 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 27.453 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −31.911 d6 = D6 r7 = −75.168 d7 = 0.1 Nd7 = 1.59885 νd7 = 6.52 (Aspheric surface) r8 = −83.815 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 5.799 d9 = 0.7 (Aspheric surface) r10 = 8.228 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = −407.116 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.739 d13 = 6.54 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.834 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 27.091 d15 = D15 (Aspheric surface) r16 = 25.56 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.672 d17 = D17 r18 = 11.326 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −227.342 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 = 2.88429E−05 A6 = 2.98793E−07 A8 = 0  7th surface k = 0 A4 = −2.83811E−05 A6 = 1.81353E−06 A8 = 1.62198E−08  9th surface k = 0 A4 = −4.89938E−04 A6 = −2.91999E−06 A8 = −3.73006E−07 13th surface k = 0 A4 = 5.58218E−05 A6 = 1.85250E−06 A8 = −3.45414E−09 15th surface k = 0 A4 = 6.90896E−04 A6 = 1.56789E−05 A8 = 7.47064E−07 18th surface k = 0 A4 = −8.76384E−05 A6 = 8.91453E−06 A8 = −1.89454E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.42 17.995 FNO. 3.4 5.52 6.68 D6 0.41 7.3 8.56 D11 11.8 3.71 0.48 D12 7.08 1.49 0.4 D15 1.1 11.71 14.56 D17 1.54 2.07 3.45 D19 4.85 1.28 0.4 D23 1.36 1.36 1.36

Seventh Embodiment

FIG. 13 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a seventh embodiment of the present invention.

FIG. 14A, FIG. 14B, and FIG. 14C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the seventh embodiment, where, FIG. 14A shows the state at the wide angle end, FIG. 14B shows the intermediate state, and FIG. 14C shows the state at the telephoto end.

The zoom lens of the seventh embodiment, as shown in FIG. 13, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a negative meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a biconvex lens L123, and has a negative refracting power as a whole. The negative meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the negative meniscus lens L121 having the convex surface directed toward the image side, and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the seventh embodiment will be enumerated.

Numerical data 7 r1 = 22.655 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 8.785 d2 = 3.24 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 28.098 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −33.03 d6 = D6 r7 = −73.397 d7 = 0.1 Nd7 = 1.79525 νd7 = 9.95 (Aspheric surface) r8 = −88.456 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 5.854 d9 = 0.7 (Aspheric surface) r10 = 8.306 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = −244.362 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.717 d13 = 6.62 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.82 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 26.804 d15 = D15 (Aspheric surface) r16 = 38.158 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 10.759 d17 = D17 r18 = 11.628 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −136.914 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 = 2.99107E−05 A6 = 2.84593E−07 A8 = 0  7th surface k = 0 A4 = −1.93689E−05 A6 = 1.33119E−06 A8 = 2.74251E−08  9th surface k = 0 A4 = −4.76470E−04 A6 = −3.16782E−06 A8 = −3.04345E−07 13th surface k = 0 A4 = 5.07612E−05 A6 = 1.80052E−06 A8 = −5.82045E−09 15th surface k = 0 A4 = 6.95232E−04 A6 = 1.61806E−05 A8 = 7.52248E−07 18th surface k = 0 A4 = −9.66932E−05 A6 = 8.24751E−06 A8 = −1.78280E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.414 17.987 FNO. 3.46 5.61 6.76 D6 0.64 7.62 8.96 D11 12.56 3.88 0.5 D12 6.75 1.31 0.4 D15 1.16 11.69 14.54 D17 1.54 2.07 3.45 D19 4.85 1.28 0.4 D23 1.36 1.36 1.36

Eighth Embodiment

FIG. 15 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eighth embodiment of the present invention.

FIG. 16A, FIG. 16B, and FIG. 16C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eighth embodiment, where, FIG. 16A shows the state at the wide angle end, FIG. 16B shows the intermediate state, and FIG. 16C shows the state at the telephoto end.

The zoom lens of the eighth embodiment, as shown in FIG. 15, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a negative meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a biconvex lens L123, and has a negative refracting power as a whole. The negative meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the negative meniscus lens L121 having the convex surface directed toward the object side, and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the eighth embodiment will be enumerated.

Numerical data 8 r1 = 22.918 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 8.816 d2 = 3.29 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 28.613 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −32.117 d6 = D6 r7 = −65.160 d7 = 0.1 Nd7 = 1.9712 νd7 = 12.88 (Aspheric surface) r8 = −81.741 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 5.883 d9 = 0.7 (Aspheric surface) r10 = 8.372 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = −174.482 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.706 d13 = 6.66 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.835 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 26.735 d15 = D15 (Aspheric surface) r16 = 45.204 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 11.103 d17 = D17 r18 = 11.758 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −117.417 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 = 2.87784E−05 A6 = 2.66348E−07 A8 = 0  7th surface k = 0 A4 = −1.38102E−05 A6 = 1.38465E−06 A8 = 2.55312E−08  9th surface k = 0 A4 = −4.75969E−04 A6 = −3.07587E−06 A8 = −2.61770E−07 13th surface k = 0 A4 = 4.93597E−05 A6 = 1.70693E−06 A8 = −4.25329E−09 15th surface k = 0 A4 = 7.00683E−04 A6 = 1.60807E−05 A8 = 7.69068E−07 18th surface k = 0 A4 = −9.75190E−05 A6 = 7.97130E−06 A8 = −1.72283E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.42 17.995 FNO. 3.5 5.64 6.81 D6 1.05 7.71 9.02 D11 13.1 3.96 0.63 D12 6.34 1.25 0.33 D15 1.21 11.71 14.56 D17 1.54 2.07 3.45 D19 4.85 1.28 0.4 D23 1.36 1.36 1.36

Ninth Embodiment

FIG. 17 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a ninth embodiment of the present invention.

FIG. 18A, FIG. 18B, and FIG. 18C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the ninth embodiment, where, FIG. 18A shows the state at the wide angle end, FIG. 18B shows the intermediate state, and FIG. 18C shows the state at the telephoto end.

The zoom lens of the ninth embodiment, as shown in FIG. 17, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a negative meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a biconvex lens L123, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the negative meniscus lens L121 having the convex surface directed toward the image side and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the ninth embodiment will be enumerated.

Numerical data 9 r1 = 22.569 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 8.775 d2 = 3.24 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 28.397 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −30.066 d6 = D6 r7 = −68.946 d7 = 0.1 Nd7 = 2.0512 νd7 = 6.28 (Aspheric surface) r8 = −72.063 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 5.835 d9 = 0.7 (Aspheric surface) r10 = 8.288 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = −350.22 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.762 d13 = 6.44 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.924 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 27.463 d15 = D15 (Aspheric surface) r16 = 18.162 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 8.571 d17 = D17 r18 = 11.048 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −683.995 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 = 2.65390E−05 A6 = 2.74957E−07 A8 = 0  7th surface k = 0 A4 = −3.03094E−05 A6 = 2.50533E−06 A8 = −2.39841E−08  9th surface k = 0 A4 = −5.10845E−04 A6 = 1.79630E−07 A8 = −4.24947E−07 13th surface k = 0 A4 = 6.06181E−05 A6 = 1.82150E−06 A8 = 5.55091E−09 15th surface k = 0 A4 = 6.87453E−04 A6 = 1.41002E−05 A8 = 7.95382E−07 18th surface k = 0 A4 = −7.29457E−05 A6 = 9.71422E−06 A8 = −2.00168E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.42 17.997 FNO. 3.33 5.43 6.58 D6 0.81 7.75 9.07 D11 10.99 3.5 0.4 D12 7.32 1.62 0.4 D15 0.99 11.73 14.54 D17 1.54 2.07 3.45 D19 4.85 1.28 0.4 D23 1.36 1.36 1.36

Tenth Embodiment

FIG. 19 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a tenth embodiment of the present invention.

FIG. 20A, FIG. 20B, and FIG. 20C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the tenth embodiment, where, FIG. 20A shows the state at the wide angle end, FIG. 20B shows the intermediate state, and FIG. 20C shows the state at the telephoto end.

The zoom lens of the tenth embodiment, as shown in FIG. 19, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having the convex surface directed toward the object side, and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the tenth embodiment will be enumerated.

Numerical data 10 r1 = 47.465 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 = 10.5 d2 = 0.35 Nd2 = 1.41244 νd2 = 12.42 r3 = 10.870 d3 = 3 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 37.541 d6 = 2.2 Nd6 = 1.8061 νd6 = 40.92 (Aspheric surface) r7 = −15.157 d7 = 0.7 Nd7 = 1.51742 νd7 = 52.43 r8 = 14.284 d8 = D8 r9 = 15.765 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −49.098 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −12.613 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 8.154 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 23.649 d15 = D15 r16 = 12.829 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −15.292 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = 3.50409E−05 A6 = −6.55294E−07 A8 = 0  6th surface k = 0 A4 = 2.65545E−05 A6 = −4.67758E−08 A8 = 0.00000E+00  9th surface k = 0 A4 = −1.42649E−05 A6 = 8.45141E−10 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.91950E−04 A6 = 6.33278E−09 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.003 13.7 17.998 FNO. 2.86 3.43 3.76 D8 14.55 4.16 0.8 D11 1.6 11.99 15.35 D12 1.4 6.55 9.17 D15 6.27 4.39 3 D18 5.7 2.43 1.2 D22 1.36 1.36 1.36

Eleventh Embodiment

FIG. 21 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eleventh embodiment of the present invention.

FIG. 22A, FIG. 22B, and FIG. 22C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eleventh embodiment, where, FIG. 22A shows the state at the wide angle end, FIG. 22B shows the intermediate state, and FIG. 22C shows the state at the telephoto end.

The zoom lens of the eleventh embodiment, as shown in FIG. 21, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a negative meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface toward the image side of the negative meniscus lens L212 having the convex surface directed toward the object side, and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the eleventh embodiment will be enumerated.

Numerical data 11 r1 = 40.805 d1 = 1.1 Nd1 = 1.741 νd1 = 52.64 r2 = 10.5 d2 = 0.35 Nd2 = 1.42001 νd2 = 6.55 r3 = 9.747 d3 = 3.1 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 36.922 d6 = 2.5 Nd6 = 1.8044 νd6 = 39.59 (Aspheric surface) r7 = −17 d7 = 0.7 Nd7 = 1.51742 νd7 = 52.43 r8 = 15.572 d8 = D8 r9 = 17.084 d9 = 3.5 Nd9 = 1.744 νd9 = 44.78 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −43.272 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −14.083 d13 = 0.7 Nd13 = 1.51633 νd13 = 64.14 r14 = 7.851 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 20.05 d15 = D15 r16 = 11.795 d16 = 3.5 Nd16 = 1.741 νd16 = 52.64 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −17.498 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = −2.71091E−06 A6 = −1.15364E−06 A8 = 0  6th surface k = 0 A4 = 2.35221E−05 A6 = 6.05500E−08 A8 = 0.00000E+00  9th surface k = 0 A4 = −9.17809E−06 A6 = −1.04149E−07 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.87144E−04 A6 = 1.47652E−06 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 5.996 13.701 18.006 FNO. 2.86 3.43 3.76 D8 15.07 3.93 0.8 D11 1.61 12.75 15.88 D12 1.41 6.07 9.49 D15 6.44 4.89 3 D18 5.89 2.77 1.25 D22 1.36 1.36 1.36

Twelfth Embodiment

FIG. 23 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twelfth embodiment of the present invention.

FIG. 24A, FIG. 24B, and FIG. 24 c are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twelfth embodiment, where, FIG. 24A shows the state at the wide angle end, FIG. 24B shows the intermediate state, and FIG. 24C shows the state at the telephoto end.

The zoom lens of the twelfth embodiment, as shown in FIG. 23, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a negative meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the negative meniscus lens L212 having the convex surface directed toward the object side, and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the twelfth embodiment will be enumerated.

Numerical data 12 r1 = 35.33 d1 = 1.1 Nd1 = 1.741 νd1 = 52.64 r2 = 10.5 d2 = 0.35 Nd2 = 1.5184 νd2 = 12.85 r3 = 10.179 d3 = 3 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 83.310 d6 = 2.2 Nd6 = 1.8044 νd6 = 39.59 (Aspheric surface) r7 = −15.779 d7 = 0.7 Nd7 = 1.51742 νd7 = 52.43 r8 = 17.653 d8 = D8 r9 = 15.957 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −38.464 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −13.171 d13 = 0.7 Nd13 = 1.51633 νd13 = 64.14 r14 = 8.317 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 22.704 d15 = D15 r16 = 11.950 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −17.693 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = −3.96738E−06 A6 = −5.13102E−07 A8 = 0  6th surface k = 0 A4 = 2.05601E−05 A6 = 1.80893E−07 A8 = 0.00000E+00  9th surface k = 0 A4 = −1.68018E−05 A6 = −1.63553E−07 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.70700E−04 A6 = 9.68010E−07 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.003 13.7 17.999 FNO. 2.86 3.43 3.76 D8 14.15 3.94 0.8 D11 1.6 11.81 14.95 D12 1.4 5.91 9.56 D15 6.85 5.36 3 D18 5.53 2.51 1.23 D22 1.36 1.36 1.36

Thirteenth Embodiment

FIG. 25 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirteenth embodiment of the present invention.

FIG. 26A, FIG. 26B, and FIG. 26C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirteenth embodiment, where, FIG. 26A shows the state at the wide angle end, FIG. 26B shows the intermediate state, and FIG. 26C shows the state at the telephoto end.

The zoom lens of the thirteenth embodiment, as shown in FIG. 25, has in order from an object side thereof, a first lens group G1, a second lens group G2, and aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirteenth embodiment will be enumerated.

Numerical data 13 r1 = 34.024 d1 = 1.1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.5 d2 = 0.35 Nd2 = 1.54856 νd2 = 7.04 r3 = 10.855 d3 = 3 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 42.711 d6 = 2.2 Nd6 = 1.8061 νd6 = 40.92 (Aspheric surface) r7 = −18.562 d7 = 0.7 Nd7 = 1.51742 νd7 = 52.43 r8 = 14.066 d8 = D8 r9 = 15.115 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −38.815 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −12.644 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 8.31 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 24.052 d15 = D15 r16 = 13.981 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −14.538 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = 4.16028E−05 A6 = −5.41690E−07 A8 = 0.00000E+00  6th surface k = 0 A4 = 4.63265E−05 A6 = −1.97237E−09 A8 = −421441E−07  9th surface k = 0 A4 = −2.78841E−05 A6 = −7.95828E−08 A8 = −1.28129E−06 16th surface k = 0 A4 = −1.82008E−04 A6 = −7.79912E−07 A8 = 5.27383E−08 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.002 13.702 17.994 FNO. 2.87 3.43 3.76 D8 13.83 4.04 0.8 D11 1.6 11.39 14.64 D12 1.4 5.72 8.81 D15 6.18 5.01 3 D18 5.42 2.26 1.19 D22 1.36 1.36 1.36

Fourteenth Embodiment

FIG. 27 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fourteenth embodiment of the present invention.

FIG. 28A, FIG. 28B, and FIG. 28C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fourteenth embodiment, where, FIG. 28A shows the state at the wide angle end, FIG. 28B shows the intermediate state, and FIG. 28C shows the state at the telephoto end.

The zoom lens of the fourteenth embodiment, as shown in FIG. 27, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a negative meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface toward the image side of the negative meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the fourteenth embodiment will be enumerated.

Numerical data 14 r1 = 35.627 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 = 10.5 d2 = 0.35 Nd2 = 1.65228 νd2 = 12.75 r3 = 10.257 d3 = 3.39 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 189.603 d6 = 2.53 Nd6 = 1.8061 νd6 = 40.92 (Aspheric surface) r7 = −14.57 d7 = 5.4 Nd7 = 1.51742 νd7 = 52.43 r8 = 18.292 d8 = D8 r9 = 17.196 d9 = 4.28 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 2.17 Nd10 = 1.84666 νd10 = 23.78 r11 = −32.13 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −16.531 d13 = 0.9 Nd13 = 1.51823 νd13 = 58.9 r14 = 7.005 d14 = 1.57 Nd14 = 1.8061 νd14 = 40.92 r15 = 21.588 d15 = D15 r16 = 14.073 d16 = 3.44 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 1.56 Nd17 = 1.84666 νd17 = 23.78 r18 = −20.07 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = 4.66886E−05 A6 = −3.68390E−07 A8 = 0  6th surface k = 0 A4 = 4.41308E−05 A6 = −1.09516E−08 A8 = 0.00000E+00  9th surface k = 0 A4 = −3.06648E−05 A6 = −2.07782E−08 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.41284E−04 A6 = −9.64511E−07 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.099 13.417 17.991 FNO. 3.26 3.52 4.58 D8 13.95 3.68 0.4 D11 0.4 12.53 12.79 D12 1.57 4.97 12.55 D15 6.19 5.04 3.12 D18 5.41 2.24 1.07 D22 1.36 1.36 1.36

Fifteenth Embodiment

FIG. 29 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fifteenth embodiment of the present invention.

FIG. 30A, FIG. 30B, and FIG. 30C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fifteenth embodiment, where, FIG. 30A shows the state at the wide angle end, FIG. 30B shows the intermediate state, and FIG. 30C shows the state at the telephoto end.

The zoom lens of the fifteenth embodiment, as shown in FIG. 29, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group.

Next, numerical data of the fifteenth embodiment will be enumerated.

Numerical data 15 r1 = 30.82 d1 = 1.1 Nd1 = 1.68184 νd1 = 39.35 r2 = 10.5 d2 = 0.35 Nd2 = 1.59885 νd2 = 6.52 r3 = 10.648 d3 = 4.65 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 134.153 d6 = 3.23 Nd6 = 1.82682 νd6 = 41.39 (Aspheric surface) r7 = −12.852 d7 = 0.7 Nd7 = 1.54352 νd7 = 51.79 r8 = 17.506 d8 = D8 r9 = 19.026 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −34.264 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −18.881 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 6.389 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 20.689 d15 = D15 r16 = 13.519 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −33.096 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = 6.29124E−05 A6 = −9.94304E−08 A8 = 0  6th surface k = 0 A4 = 3.57536E−05 A6 = −2.19825E−07 A8 = 0.00000E+00  9th surface k = 0 A4 = −2.33627E−05 A6 = 1.44142E−07 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.46902E−04 A6 = −2.18220E−06 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.421 17.996 FNO. 3.36 3.86 4.73 D8 23.43 6.51 1.75 D11 1.47 10 10.6 D12 0.53 6.33 13.1 D15 6.2 5.15 3.36 D18 5.4 2.12 0.82 D22 1.36 1.36 1.36

Sixteenth Embodiment

FIG. 31 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a sixteenth embodiment of the present invention.

FIG. 32A, FIG. 32B, and FIG. 32C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the sixteenth embodiment, where, FIG. 32A shows the state at the wide angle end, FIG. 32B shows the intermediate state, and FIG. 32C shows the state at the telephoto end.

The zoom lens of the sixteenth embodiment, as shown in FIG. 31, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens L222 which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the sixteenth embodiment will be enumerated.

Numerical data 16 r1 = 31.869 d1 = 1.1 Nd1 = 1.68455 νd1 = 38.62 r2 = 10.5 d2 = 0.35 Nd2 = 1.79525 νd2 = 9.95 r3 = 10.719 d3 = 4.19 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 99.427 d6 = 3.24 Nd6 = 1.82739 νd6 = 42.49 (Aspheric surface) r7 = −13.299 d7 = 0.7 Nd7 = 1.54227 νd7 = 52.3 r8 = 16.692 d8 = D8 r9 = 19.193 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −33.527 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −18.855 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 6.427 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 21.117 d15 = D15 r16 = 14.070 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −30.061 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = 5.65707E−05 A6 = −8.35153E−09 A8 = 0  6th surface k = 0 A4 = 4.41416E−05 A6 = −2.42655E−07 A8 = 0.00000E+00  9th surface k = 0 A4 = −2.48396E−05 A6 = 1.43316E−07 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.47665E−04 A6 = −2.52326E−06 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.42 17.995 FNO. 3.35 3.84 4.67 D8 23.69 6.89 2.16 D11 1.33 9.95 10.69 D12 0.53 6.23 12.79 D15 6.2 5.15 3.38 D18 5.4 2.12 0.81 D22 1.36 1.36 1.36

Seventeenth Embodiment

FIG. 33 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a seventeenth embodiment of the present invention.

FIG. 34A, FIG. 34B, and FIG. 34C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the seventeenth embodiment, where, FIG. 34A shows the state at the wide angle end, FIG. 34B shows the intermediate state, and FIG. 34C shows the state at the telephoto end.

The zoom lens of the seventeenth embodiment, as shown in FIG. 33, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the seventeenth embodiment will be enumerated.

Numerical data 17 r1 = 36.23 d1 = 1.1 Nd1 = 1.69029 νd1 = 36.36 r2 = 10.5 d2 = 0.35 Nd2 = 1.9712 νd2 = 12.88 r3 = 11.000 d3 = 3.93 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 88.421 d6 = 2.2 Nd6 = 1.82354 νd6 = 44.73 (Aspheric surface) r7 = −14.187 d7 = 0.7 Nd7 = 1.53704 νd7 = 54.58 r8 = 16.455 d8 = D8 r9 = 18.958 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −32.852 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −18.113 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 6.38 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 20.833 d15 = D15 r16 = 13.828 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −29.055 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = 5.07303E−05 A6 = −6.94190E−08 A8 = 0  6th surface k = 0 A4 = 4.89135E−05 A6 = −2.70777E−07 A8 = 0.00000E+00  9th surface k = 0 A4 = −2.69831E−05 A6 = 1.67783E−07 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.51906E−04 A6 = −2.58667E−06 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.106 13.462 18.001 FNO. 3.32 3.76 4.59 D8 22.99 6.9 2.3 D11 1.19 10.06 10.8 D12 0.53 5.88 12.39 D15 6.19 5.13 3.33 D18 5.4 2.14 0.85 D22 1.36 1.36 1.36

Eighteenth Embodiment

FIG. 35 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eighteenth embodiment of the present invention.

FIG. 36A, FIG. 36B, and FIG. 36C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eighteenth embodiment, where, FIG. 36A shows the state at the wide angle end, FIG. 36B shows the intermediate state, and FIG. 36C shows the state at the telephoto end.

The zoom lens of the eighteenth embodiment, as shown in FIG. 35, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the eighteenth embodiment will be enumerated.

Numerical data 18 r1 = 31.999 d1 = 1.1 Nd1 = 1.71082 νd1 = 36.25 r2 = 10.5 d2 = 0.35 Nd2 = 2.0512 νd2 = 6.28 r3 = 10.544 d3 = 4.21 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 81.783 d6 = 2.2 Nd6 = 1.81694 νd6 = 45.25 (Aspheric surface) r7 = −15.2 d7 = 0.7 Nd7 = 1.53247 νd7 = 56.77 r8 = 16.515 d8 = D8 r9 = 18.404 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −33.096 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −16.544 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 6.208 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 20.648 d15 = D15 r16 = 12.668 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −34.221 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = 3.63151E−05 A6 = −1.62265E−07 A8 = 0  6th surface k = 0 A4 = 4.72473E−05 A6 = −1.61277E−07 A8 = 0.00000E+00  9th surface k = 0 A4 = −2.67300E−05 A6 = 1.00083E−07 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.61823E−04 A6 = −2.44296E−06 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.42 17.995 FNO. 3.3 3.75 4.63 D8 21.27 6.21 1.88 D11 1.45 10.47 11.12 D12 0.54 5.9 12.67 D15 6.19 5.11 3.29 D18 5.4 2.16 0.9 D22 1.36 1.36 1.36

Nineteenth Embodiment

FIG. 37 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a nineteenth embodiment of the present invention.

FIG. 38A, FIG. 38B, and FIG. 38C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the nineteenth embodiment of the present invention, where, FIG. 38A shows the state at the wide angle end, FIG. 38B shows the intermediate state, and FIG. 38C shows the state at the telephoto end.

The zoom lens of the nineteenth embodiment, as shown in FIG. 37, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a positive meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a positive meniscus lens L123 having a convex surface directed toward the object side, and has a negative refracting power as a whole. The positive meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the positive meniscus lens L121 having the convex surface directed toward the image side and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the nineteenth embodiment will be enumerated.

Numerical data 19 r1 = 26.23 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.006 d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 29.400 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −27.224 d6 = D6 r7 = −427.532 d7 = 0.1 Nd7 = 1.60687 νd7 = 27.03 (Aspheric surface) r8 = −85.507 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 5.812 d9 = 0.7 (Aspheric surface) r10 = 7.784 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = 57.223 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.919 d13 = 5.77 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −11.83 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 30.159 d15 = D15 (Aspheric surface) r16 = 31.89 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.783 d17 = D17 r18 = 9.927 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −446.12 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 = 7.16645E−06 A6 = 2.11964E−07 A8 = 0.00000E+00  7th surface k = 0 A4 = −2.74688E−04 A6 = 1.59082E−05 A8 = −4.11894E−07  9th surface k = 0 A4 = −6.19261E−04 A6 = 1.66320E−05 A8 = −1.07465E−06 13th surface k = 0 A4 = 1.19177E−04 A6 = 1.52490E−06 A8 = 5.07043E−08 15th surface k = 0 A4 = 7.35553E−04 A6 = 6.73062E−06 A8 = 9.72233E−07 18th surface k = 0 A4 = −8.48549E−05 A6 = 7.84254E−06 A8 = −2.08776E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.004 13.699 17.993 FNO. 2.88 4.93 6.03 D6 0.8 6.9 8.34 D11 8.93 2.83 1.38 D12 11.66 3.89 1.19 D15 1.21 12.03 14.22 D17 1.52 2.04 3.34 D19 4.87 1.31 0.51 D23 1.36 1.36 1.36

Twentieth Embodiment

FIG. 39 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twentieth embodiment of the present invention.

FIG. 40A, FIG. 40B, and FIG. 40C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twentieth embodiment, where, FIG. 40A shows the state at the wide angle end, FIG. 40B shows the intermediate state, and FIG. 40C shows the state at the telephoto end.

The zoom lens of the twentieth embodiment, as shown in FIG. 39, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a positive meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a positive meniscus lens L123 having a convex surface directed toward the object side, and has a negative refracting power as a whole. The positive meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the positive meniscus lens L121 having the convex surface directed toward the image side and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twentieth embodiment will be enumerated.

Numerical data 20 r1 = 28.665 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.332 d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 31.049 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −27.405 d6 = D6 r7 = −597.656 d7 = 0.1 Nd7 = 1.60258 νd7 = 18.58 (Aspheric surface) r8 = −119.531 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 6.192 d9 = 0.7 (Aspheric surface) r10 = 7.977 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = 44.985 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.062 d13 = 6.69 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −12.133 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 25.526 d15 = D15 (Aspheric surface) r16 = 31.796 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.85 d17 = D17 r18 = 9.439 d18 = 2.42 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −317.346 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 = 1.05193E−05 A6 = 1.66357E−07 A8 = 0  7th surface k = 0 A4 = −2.89743E−06 A6 = −8.65818E−07 A8 = −3.60260E−08  9th surface k = 0 A4 = −2.70650E−04 A6 = 8.31779E−07 A8 = −4.74154E−07 13th surface k = 0 A4 = 5.75822E−05 A6 = 8.18087E−07 A8 = 1.34700E−08 15th surface k = 0 A4 = 6.34095E−04 A6 = 7.55761E−06 A8 = 6.75722E−07 18th surface k = 0 A4 = −9.39679E−05 A6 = 5.02231E−06 A8 = −1.47714E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.133 13.699 17.991 FNO. 2.88 4.79 6.09 D6 0.78 7.36 8.04 D11 8.65 2.07 1.39 D12 12.47 4.62 1.19 D15 1.2 12.36 16.53 D17 1.58 0.99 1.32 D19 4.3 1.58 0.5 D23 1.36 1.36 1.36

Twenty First Embodiment

FIG. 41 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty first embodiment of the present invention.

FIG. 42A, FIG. 42B, and FIG. 42C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty first embodiment, where, FIG. 42A shows the state at the wide angle end, FIG. 42B shows the intermediate state, and FIG. 42C shows the state at the telephoto end.

The zoom lens of the twenty first embodiment, as shown in FIG. 41, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a positive meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a positive meniscus lens L123 having a convex surface directed toward the object side, and has a negative refracting power as a whole. The positive meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the positive meniscus lens L121 having the convex surface directed toward the image side and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty first embodiment will be enumerated.

Numerical data 21 r1 = 26.273 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.996 d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 29.453 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −27.281 d6 = D6 r7 = −427.470 d7 = 0.1 Nd7 = 1.69556 νd7 = 25.02 (Aspheric surface) r8 = −85.503 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 5.809 d9 = 0.7 (Aspheric surface) r10 = 7.788 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = 57.059 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.923 d13 = 5.77 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −11.824 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 30.104 d15 = D15 (Aspheric surface) r16 = 31.829 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.789 d17 = D17 r18 = 9.921 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −432.356 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients 5th surface k = 0 A4 = 7.43080E−06 A6 = 2.36674E−07 A8 = 0 7th surface k = 0 A4 = −2.72694E−04 A6 = 1.59428E−05 A8 = −4.43258E−07 9th surface k = 0 A4 = −6.24015E−04 A6 = 1.59447E−05 A8 = −1.12342E−06 13th surface k = 0 A4 = 1.19650E−04 A6 = 1.56558E−06 A8 = 5.16124E−08 15th surface k = 0 A4 = 7.34872E−04 A6 = 6.85852E−06 A8 = 1.00204E−06 18th surface k = 0 A4 = −8.49934E−05 A6 = 7.83157E−06 A8 = −1.99542E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.022 13.693 17.99 FNO. 2.89 4.93 6.04 D6 0.8 6.9 8.34 D11 8.93 2.83 1.38 D12 11.66 3.89 1.19 D15 1.21 12.03 14.22 D17 1.52 2.04 3.34 D19 4.87 1.31 0.51 D23 1.33 1.26 1.19

Twenty Second Embodiment

FIG. 43 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty second embodiment of the present invention.

FIG. 44A, FIG. 44B, and FIG. 44C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty second embodiment, where, FIG. 44A shows the state at the wide angle end, FIG. 44B shows the intermediate state, and FIG. 44C shows the state at the telephoto end.

The zoom lens of the twenty second embodiment, as shown in FIG. 43, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a positive meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a positive meniscus lens L123 having a convex surface directed toward the object side, and has a negative refracting power as a whole. The positive meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the positive meniscus lens L121 having the convex surface directed toward the image side and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty second embodiment will be enumerated.

Numerical data 22 r1 = 28.153 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.001 d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 32.505 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −25.917 d6 = D6 r7 = −740.857 d7 = 0.1 Nd7 = 1.72568 νd7 = 18.68 (Aspheric surface) r8 = −148.171 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 6.310 d9 = 0.7 (Aspheric surface) r10 = 8.047 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = 44.374 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.280 d13 = 6.86 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −12.441 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 23.674 d15 = D15 (Aspheric surface) r16 = 32.089 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 10.246 d17 = D17 r18 = 8.999 d18 = 2.84 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −336.916 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients 5th surface k = 0 A4 = 1.44713E−05 A6 = 1.83334E−07 A8 = 0 7th surface k = 0 A4 = 1.00296E−04 A6 = −2.66735E−06 A8 = −7.23998E−08 9th surface k = 0 A4 = −1.44775E−04 A6 = 1.13466E−06 A8 = −6.29859E−07 13th surface k = 0 A4 = 4.09141E−05 A6 = 1.46004E−06 A8 = −1.30523E−09 15th surface k = 0 A4 = 5.36585E−04 A6 = 9.23484E−06 A8 = 5.21540E−07 18th surface k = 0 A4 = −1.13762E−04 A6 = 2.57069E−06 A8 = −7.70554E−08 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.009 13.699 17.994 FNO. 2.88 4.75 6 D6 0.8 8.29 9.18 D11 9.78 2.28 1.39 D12 12.74 4.65 1.19 D15 1.2 12.65 17.78 D17 2.07 1.02 0.52 D19 3.98 1.67 0.5 D23 1.36 1.36 1.36

Twenty Third Embodiment

FIG. 45 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty third embodiment of the present invention.

FIG. 46A, FIG. 46B, and FIG. 46C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty third embodiment, where, FIG. 46A shows the state at the wide angle end, FIG. 46B shows the intermediate state, and FIG. 46C shows the state at the telephoto end.

The zoom lens of the twenty third embodiment, as shown in FIG. 45, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a positive meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a positive meniscus lens L123 having a convex surface directed toward the object side, and has a negative refracting power as a whole. The positive meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the positive meniscus lens L121 having the convex surface directed toward the image side and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty third embodiment will be enumerated.

Numerical data 23 r1 = 28.511 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.994 d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 38.094 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −24.225 d6 = D6 r7 = −1274.407 d7 = 0.1 Nd7 = 1.852 νd7 = 14.02 (Aspheric surface) r8 = −254.882 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 6.154 d9 = 0.7 (Aspheric surface) r10 = 7.986 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = 49.528 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.197 d13 = 6.63 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −12.225 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 24.043 d15 = D15 (Aspheric surface) r16 = 32.547 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.657 d17 = D17 r18 = 9.134 d18 = 3.3 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −352.2 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients 5th surface k = 0 A4 = 1.39794E−05 A6 = 4.83461E−08 A8 = 0 7th surface k = 0 A4 = −9.91992E−05 A6 = 9.49659E−06 A8 = −1.70473E−07 9th surface k = 0 A4 = −4.20046E−04 A6 = 1.34294E−05 A8 = −4.94118E−07 13th surface k = 0 A4 = 4.51915E−05 A6 = 1.87715E−06 A8 = 1.74240E−08 15th surface k = 0 A4 = 6.19553E−04 A6 = 3.11453E−07 A8 = 1.16717E−06 18th surface k = 0 A4 = −8.62916E−05 A6 = 2.48715E−06 A8 = −6.25373E−08 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.025 13.7 17.984 FNO. 2.88 4.64 5.86 D6 0.78 9.1 10 D11 10.6 2.28 1.38 D12 12.19 4.66 1.18 D15 1.18 12.47 17.95 D17 2.51 1.08 0.33 D19 4.09 1.76 0.5 D23 1.36 1.36 1.36

Twenty Fourth Embodiment

FIG. 47 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty fourth embodiment of the present invention.

FIG. 48A, FIG. 48B, and FIG. 48C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty fourth embodiment, where, FIG. 48A shows the state at the wide angle end, FIG. 48B shows the intermediate state, and FIG. 48C shows the state at the telephoto end.

The zoom lens of the twenty fourth embodiment, as shown in FIG. 47, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a negative meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a positive meniscus lens L123 having a convex surface directed toward the object side, and has a negative refracting power as a whole. The negative meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the negative meniscus lens L121 having the convex surface directed toward the image side and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty fourth embodiment will be enumerated.

Numerical data 24 r1 = 22.06 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 8.728 d2 = 3.48 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 30.986 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −27.99 d6 = D6 r7 = −115.268 d7 = 0.1 Nd7 = 1.65228 νd7 = 12.75 (Aspheric surface) r8 = −126.689 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 5.968 d9 = 0.7 (Aspheric surface) r10 = 8.311 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = 176.709 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.790 d13 = 6.26 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −11.462 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 28.003 d15 = D15 (Aspheric surface) r16 = 15.819 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 8.139 d17 = D17 r18 = 11.145 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −741.85 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients 5th surface k = 0 A4 = 2.56867E−05 A6 = 2.52676E−07 A8 = 0 7th surface k = 0 A4 = −1.22696E−04 A6 = 8.55567E−06 A8 = −7.67236E−08 9th surface k = 0 A4 = −5.12267E−04 A6 = 4.37980E−06 A8 = −3.04805E−07 13th surface k = 0 A4 = 6.62474E−05 A6 = 1.59411E−06 A8 = 2.28358E−08 15th surface k = 0 A4 = 6.81156E−04 A6 = 1.15567E−05 A8 = 8.59263E−07 18th surface k = 0 A4 = −5.99348E−05 A6 = 9.65602E−06 A8 = −1.88588E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.42 17.995 FNO. 3.27 5.28 6.49 D6 1.53 8.13 9.28 D11 11.01 2.98 0.41 D12 7.5 2.21 0.4 D15 0.9 11.71 14.54 D17 1.54 2.08 3.46 D19 4.85 1.27 0.39 D23 1.36 1.36 1.36

Twenty Fifth Embodiment

FIG. 49 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty fifth embodiment of the present invention.

FIG. 50A, FIG. 50B, and FIG. 50C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty fifth embodiment, where, FIG. 50A shows the state at the wide angle end, FIG. 50B shows the intermediate state, and FIG. 50C shows the state at the telephoto end.

The zoom lens of the twenty fifth embodiment, as shown in FIG. 49, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagrams, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a negative meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a biconvex lens L123, and has a negative refracting power as a whole. The negative meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the negative meniscus lens L121 having the convex surface directed toward the image side and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty fifth embodiment will be enumerated.

Numerical data 25 r1 = 22.209 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 8.697 d2 = 3.18 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 27.453 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −31.911 d6 = D6 r7 = −75.168 d7 = 0.1 Nd7 = 1.59885 νd7 = 6.52 (Aspheric surface) r8 = −83.815 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 5.799 d9 = 0.7 (Aspheric surface) r10 = 8.228 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = −407.116 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.739 d13 = 6.54 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.834 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 27.091 d15 = D15 (Aspheric surface) r16 = 25.56 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.672 d17 = D17 r18 = 11.326 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −227.342 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients 5th surface k = 0 A4 = 2.88429E−05 A6 = 2.98793E−07 A8 = 0 7th surface k = 0 A4 = −2.83811E−05 A6 = 1.81353E−06 A8 = 1.62198E−08 9th surface k = 0 A4 = −4.89938E−04 A6 = −2.91999E−06 A8 = −3.73006E−07 13th surface k = 0 A4 = 5.58218E−05 A6 = 1.85250E−06 A8 = −3.45414E−09 15th surface k = 0 A4 = 6.90896E−04 A6 = 1.56789E−05 A8 = 7.47064E−07 18th surface k = 0 A4 = −8.76384E−05 A6 = 8.91453E−06 A8 = −1.89454E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.42 17.995 FNO. 3.4 5.52 6.68 D6 0.41 7.3 8.56 D11 11.8 3.71 0.48 D12 7.08 1.49 0.4 D15 1.1 11.71 14.56 D17 1.54 2.07 3.45 D19 4.85 1.28 0.4 D23 1.36 1.36 1.36

Twenty Sixth Embodiment

FIG. 51 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty sixth embodiment of the present invention.

FIG. 52A, FIG. 52B, and FIG. 52C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty sixth embodiment, where, FIG. 52A shows the state at the wide angle end, FIG. 52B shows the intermediate state, and FIG. 52C shows the state at the telephoto end.

The zoom lens of the twenty sixth embodiment, as shown in FIG. 51, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a negative meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a biconvex lens L123, and has a negative refracting power as a whole. The negative meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the negative meniscus lens L121 having the convex surface directed toward the image side and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty sixth embodiment will be enumerated.

Numerical data 26 r1 = 22.655 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 8.785 d2 = 3.24 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 28.098 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −33.03 d6 = D6 r7 = −73.397 d7 = 0.1 Nd7 = 1.79525 νd7 = 9.95 (Aspheric surface) r8 = −88.456 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 5.854 d9 = 0.7 (Aspheric surface) r10 = 8.306 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = −244.362 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.717 d13 = 6.62 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.82 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 26.804 d15 = D15 (Aspheric surface) r16 = 38.158 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 10.759 d17 = D17 r18 = 11.628 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −136.914 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients 5th surface k = 0 A4 = 2.99107E−05 A6 = 2.84593E−07 A8 = 0 7th surface k = 0 A4 = −1.93689E−05 A6 = 1.33119E−06 A8 = 2.74251E−08 9th surface k = 0 A4 = −4.76470E−04 A6 = −3.16782E−06 A8 = −3.04345E−07 13th surface k = 0 A4 = 5.07612E−05 A6 = 1.80052E−06 A8 = −5.82045E−09 15th surface k = 0 A4 = 6.95232E−04 A6 = 1.61806E−05 A8 = 7.52248E−07 18th surface k = 0 A4 = −9.66932E−05 A6 = 8.24751E−06 A8 = −1.78280E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.414 17.987 FNO. 3.46 5.61 6.76 D6 0.64 7.62 8.96 D11 12.56 3.88 0.5 D12 6.75 1.31 0.4 D15 1.16 11.69 14.54 D17 1.54 2.07 3.45 D19 4.85 1.28 0.4 D23 1.36 1.36 1.36

Twenty Seventh Embodiment

FIG. 53 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty seventh embodiment of the present invention.

FIG. 54A, FIG. 54B, and FIG. 54C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty seventh embodiment, where, FIG. 54A shows the state at the wide angle end, FIG. 54B shows the intermediate state, and FIG. 54C shows the state at the telephoto end.

The zoom lens of the twenty seventh embodiment, as shown in FIG. 53, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a negative meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a biconvex lens L123, and has a negative refracting power as a whole. The negative meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the negative meniscus lens L121 having the convex surface directed toward the image side and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty seventh embodiment will be enumerated.

Numerical data 27 r1 = 22.918 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 8.816 d2 = 3.29 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 28.613 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −32.117 d6 = D6 r7 = −65.160 d7 = 0.1 Nd7 = 1.9712 νd7 = 12.88 (Aspheric surface) r8 = −81.741 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 5.883 d9 = 0.7 (Aspheric surface) r10 = 8.372 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = −174.482 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.706 d13 = 6.66 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.835 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 26.735 d15 = D15 (Aspheric surface) r16 = 45.204 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 11.103 d17 = D17 r18 = 11.758 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −117.417 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients 5th surface k = 0 A4 = 2.87784E−05 A6 = 2.66348E−07 A8 = 0 7th surface k = 0 A4 = −1.38102E−05 A6 = 1.38465E−06 A8 = 2.55312E−08 9th surface k = 0 A4 = −4.75969E−04 A6 = −3.07587E−06 A8 = −2.61770E−07 13th surface k = 0 A4 = 4.93597E−05 A6 = 1.70693E−06 A8 = −4.25329E−09 15th surface k = 0 A4 = 7.00683E−04 A6 = 1.60807E−05 A8 = 7.69068E−07 18th surface k = 0 A4 = −9.75190E−05 A6 = 7.97130E−06 A8 = −1.72283E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal 6.1 13.42 17.995 length FNO. 3.5 5.64 6.81 D6 1.05 7.71 9.02 D11 13.1 3.96 0.63 D12 6.34 1.25 0.33 D15 1.21 11.71 14.56 D17 1.54 2.07 3.45 D19 4.85 1.28 0.4 D23 1.36 1.36 1.36

Twenty Eighth Embodiment

FIG. 55 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty eighth embodiment of the present invention.

FIG. 56A, FIG. 56B, and FIG. 56C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty eighth embodiment, where, FIG. 56A shows the state at the wide angle end, FIG. 56B shows the intermediate state, and FIG. 56C shows the state at the telephoto end.

The zoom lens of the twenty eighth embodiment, as shown in FIG. 55, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a negative meniscus lens L121 having a convex surface directed toward an image side and a biconcave lens L122, and a biconvex lens L123, and has a negative refracting power as a whole. The negative meniscus lens L121 having the convex surface directed toward the image side is a lens having a thin center-thickness.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the negative meniscus lens L121 having the convex surface directed toward the image side, and a surface on the image side of the biconcave lens L122 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty eighth embodiment will be enumerated.

Numerical data 28 r1 = 22.569 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 8.775 d2 = 3.24 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 = 28.397 d5 = 3.54 Nd5 = 1.741 νd5 = 52.64 (Aspheric surface) r6 = −30.066 d6 = D6 r7 = −68.946 d7 = 0.1 Nd7 = 2.0512 νd7 = 6.28 (Aspheric surface) r8 = −72.063 d8 = 0.7 Nd8 = 1.8044 νd8 = 39.59 r9 = 5.835 d9 = 0.7 (Aspheric surface) r10 = 8.288 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 = −350.22 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.762 d13 = 6.44 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.924 d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 27.463 d15 = D15 (Aspheric surface) r16 = 18.162 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 8.571 d17 = D17 r18 = 11.048 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 = −683.995 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 = D23 Aspherical coefficients 5th surface k = 0 A4 = 2.65390E−05 A6 = 2.74957E−07 A8 = 0 7th surface k = 0 A4 = −3.03094E−05 A6 = 2.50533E−06 A8 = −2.39841E−08 9th surface k = 0 A4 = −5.10845E−04 A6 = 1.79630E−07 A8 = −4.24947E−07 13th surface k = 0 A4 = 6.06181E−05 A6 = 1.82150E−06 A8 = 5.55091E−09 15th surface k = 0 A4 = 6.87453E−04 A6 = 1.41002E−05 A8 = 7.95382E−07 18th surface k = 0 A4 = −7.29457E−05 A6 = 9.71422E−06 A8 = −2.00168E−07 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal 6.1 13.42 17.997 length FNO. 3.33 5.43 6.58 D6 0.81 7.75 9.07 D11 10.99 3.5 0.4 D12 7.32 1.62 0.4 D15 0.99 11.73 14.54 D17 1.54 2.07 3.45 D19 4.85 1.28 0.4 D23 1.36 1.36 1.36

Twenty Ninth Embodiment

FIG. 57 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty ninth embodiment of the present invention.

FIG. 58A, FIG. 58B, and FIG. 58C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty ninth embodiment, where, FIG. 58A shows the state at the wide angle end, FIG. 58B shows the intermediate state, and FIG. 58C shows the state at the telephoto end.

The zoom lens of the twenty ninth embodiment, as shown in FIG. 57, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the twenty ninth embodiment will be enumerated.

Numerical data 29 r1 = 42.623 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 = 10.5 d2 = 0.35 Nd2 = 1.60687 νd2 = 27.03 r3 = 10.955 d3 = 3 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 42.697 d6 = 2.2 Nd6 = 1.8061 νd6 = 40.92 (Aspheric surface) r7 = −18.636 d7 = 0.7 Nd7 = 1.51742 νd7 = 52.43 r8 = 14.071 d8 = D8 r9 = 15.077 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −39.184 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −12.629 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 8.282 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 24.007 d15 = D15 r16 = 14.042 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −14.453 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients 3rd surface k = 0 A4 = 3.77975E−05 A6 = −5.62278E−07 A8 = 0.00000E+00 6th surface k = 0 A4 = 4.40548E−05 A6 = −1.53391E−08 A8 = −4.21441E−07 9th surface k = 0 A4 = −2.73771E−05 A6 = −6.18132E−08 A8 = −1.28129E−06 16th surface k = 0 A4 = −1.85122E−04 A6 = −9.53942E−07 A8 = 5.27383E−08 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal 6.002 13.7 17.994 length FNO. 2.86 3.43 3.76 D8 13.83 4.04 0.8 D11 1.6 11.39 14.64 D12 1.4 5.72 8.81 D15 6.18 5.01 3 D18 5.42 2.26 1.19 D22 1.36 1.36 1.36

Thirtieth Embodiment

FIG. 59 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirtieth embodiment of the present invention.

FIG. 60A, FIG. 60B, and FIG. 60C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirtieth embodiment, where, FIG. 60A shows the state at the wide angle end, FIG. 60B shows the intermediate state, and FIG. 60C shows the state at the telephoto end.

The zoom lens of the thirtieth embodiment, as shown in FIG. 59, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirtieth embodiment will be enumerated.

Numerical data 30 r1 = 33.12 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 = 10.5 d2 = 0.35 Nd2 = 1.60258 νd2 = 18.58 r3 = 11.228 d3 = 3 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 91.734 d6 = 2.2 Nd6 = 1.8061 νd6 = 40.92 (Aspheric surface) r7 = −72.862 d7 = 0.7 Nd7 = 1.51742 νd7 = 52.43 r8 = 17.372 d8 = D8 r9 = 15.499 d9 = 3.5 Nd9 = 1.741 νd9 = 52.64 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −23.524 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −21.048 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 15.455 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 23.926 d15 = D15 r16 = 16.462 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −13.956 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients 3rd surface k = 0 A4 = 6.13709E−05 A6 = −1.03264E−06 A8 = 0 6th surface k = 0 A4 = 8.62992E−05 A6 = −9.39844E−07 A8 = 0.00000E+00 9th surface k = 0 A4 = −9.05151E−05 A6 = 6.59858E−07 A8 = 0 00000E+00 16th surface k = 0 A4 = −1.54117E−04 A6 = −3.27700E−07 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal 6.196 13.697 17.975 length FNO. 2.86 3.6 4.23 D8 11.94 3.67 0.81 D11 1.53 9.79 12.65 D12 1.37 4.96 9.39 D15 6.98 6.31 2.95 D18 5.02 2.1 1.04 D22 1.35 1.34 1.35

Thirty First Embodiment

FIG. 61 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty first embodiment of the present invention.

FIG. 62A, FIG. 62B, and FIG. 62C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty first embodiment, where, FIG. 62A shows the state at the wide angle end, FIG. 62B shows the intermediate state, and FIG. 62C shows the state at the telephoto end.

The zoom lens of the thirty first embodiment, as shown in FIG. 61, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having a convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty first embodiment will be enumerated.

Numerical data 31 r1 = 42.691 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 = 10.5 d2 = 0.35 Nd2 = 1.69556 νd2 = 25.02 r3 = 10.948 d3 = 3 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 42.763 d6 = 2.2 Nd6 = 1.8061 νd6 = 40.92 (Aspheric surface) r7 = −18.652 d7 = 0.7 Nd7 = 1.51742 νd7 = 52.43 r8 = 14.064 d8 = D8 r9 = 15.087 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −39.251 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −12.631 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 8.281 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 24.016 d15 = D15 r16 = 14.034 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −14.442 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients 3rd surface k = 0 A4 = 3.61554E−05 A6 = −5.07637E−07 A8 = 0 6th surface k = 0 A4 = 4.45689E−05 A6 = −1.88567E−08 A8 = 0.00000E+00 9th surface k = 0 A4 = −2.68975E−05 A6 = −6.60559E−08 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.85460E−04 A6 = −1.01430E−06 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal 6.025 13.747 18.059 length FNO. 2.86 3.42 3.75 D8 13.83 4.04 0.8 D11 1.6 11.39 14.64 D12 1.4 5.72 8.81 D15 6.18 5.01 3 D18 5.42 2.26 1.19 D22 1.36 1.36 1.36

Thirty Second Embodiment

FIG. 63 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty second embodiment of the present invention.

FIG. 64A, FIG. 64B, and FIG. 64C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty second embodiment, where, FIG. 64A shows the state at the wide angle end, FIG. 64B shows the intermediate state, and FIG. 64C shows the state at the telephoto end.

The zoom lens of the thirty second embodiment, as shown in FIG. 63, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a negative meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a negative meniscus lens L214 having a convex surface directed toward an image side and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a negative meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the negative meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the negative meniscus lens L214 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty second embodiment will be enumerated.

Numerical data 32 r1 = 27.755 d1 = 1.1 Nd1 = 1.713 νd1 = 53.87 r2 = 10.5 d2 = 0.35 Nd2 = 1.72568 νd2 = 18.68 r3 = 10.360 d3 = 3 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = −88.912 d6 = 2.2 Nd6 = 1.741 νd6 = 52.64 (Aspheric surface) r7 = −384.855 d7 = 0.7 Nd7 = 1.51823 νd7 = 58.9 r8 = 34.674 d8 = D8 r9 = 14.025 d9 = 3.5 Nd9 = 1.741 νd9 = 52.64 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −22.307 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −14.038 d13 = 0.7 Nd13 = 1.48749 νd13 = 70.23 r14 = 179.442 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 120.923 d15 = D15 r16 = 21.227 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −14.726 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients 3rd surface k = 0 A4 = −7.05799E−05 A6 = −6.32580E−08 A8 = 0 6th surface k = 0 A4 = −4.90530E−05 A6 = 7.20862E−07 A8 = 0.00000E+00 9th surface k = 0 A4 = −7.03137E−05 A6 = −4.20920E−07 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.18414E−04 A6 = −1.34275E−06 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal 6.149 13.699 17.989 length FNO. 2.86 2.89 3.41 D8 12.19 2.73 0.81 D11 1.63 11.09 13.01 D12 1.43 1.89 6.58 D15 3.36 5.23 2.93 D18 5.49 3.17 0.77 D22 1.34 1.34 1.34

Thirty Third Embodiment

FIG. 65 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty third embodiment of the present invention.

FIG. 66A, FIG. 66B, and FIG. 66C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty third embodiment, where, FIG. 66A shows the state at the wide angle end, FIG. 66B shows the intermediate state, and FIG. 66C shows the state at the telephoto end.

The zoom lens of the thirty third embodiment, as shown in FIG. 65, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a negative meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a negative meniscus lens L214 having a convex surface directed toward an image side and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a negative meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of moving from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the negative meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the negative meniscus lens L214 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the forth lens group G4.

Next, numerical data of the thirty third embodiment will be enumerated.

Numerical data 33 r1 = 31.726 d1 = 1.1 Nd1 = 1.713 νd1 = 53.87 r2 = 10.5 d2 = 0.35 Nd2 = 1.852 νd2 = 14.02 r3 = 10.488 d3 = 3 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = −62.156 d6 = 2.2 Nd6 = 1.741 νd6 = 52.64 (Aspheric surface) r7 = −2391.348 d7 = 0.7 Nd7 = 1.51823 νd7 = 58.9 r8 = 156.429 d8 = D8 r9 = 15.196 d9 = 3.5 Nd9 = 1.741 νd9 = 52.64 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −23.452 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −12.708 d13 = 0.7 Nd13 = 1.48749 νd13 = 70.23 r14 = 991.277 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 431.248 d15 = D15 r16 = 46.011 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −11.503 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = −7.02659E−05 A6 = −1.20251E−07 A8 = 0  6th surface k = 0 A4 = −6.03215E−05 A6 = 4.18480E−07 A8 = 0.00000E+00  9th surface k = 0 A4 = −5.02553E−05 A6 = −2.74785E−07 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.27377E−04 A6 = −7.15856E−06 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.079 13.698 18.005 FNO. 2.86 2.7 3.18 D8 13.32 2.66 0.81 D11 1.62 12.29 14.13 D12 1.42 0.98 4.94 D15 0.81 4.08 2.94 D18 6.89 4.06 1.25 D22 1.36 1.36 1.36

Thirty Fourth Embodiment

FIG. 67 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty fourth embodiment of the present invention.

FIG. 68A, FIG. 68B, and FIG. 68C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty fourth embodiment, where, FIG. 68A shows the state at the wide angle end, FIG. 68B shows the intermediate state, and FIG. 68C shows the state at the telephoto end.

The zoom lens of the thirty fourth embodiment, as shown in FIG. 67, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a negative meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the negative meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty fourth embodiment will be enumerated.

Numerical data 34 r1 = 35.627 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 = 10.5 d2 = 0.35 Nd2 = 1.65228 νd2 = 12.75 r3 = 10.257 d3 = 3.39 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 189.603 d6 = 2.53 Nd6 = 1.8061 νd6 = 40.92 (Aspheric surface) r7 = −14.57 d7 = 5.4 Nd7 = 1.51742 νd7 = 52.43 r8 = 18.292 d8 = D8 r9 = 17.196 d9 = 4.28 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 2.17 Nd10 = 1.84666 νd10 = 23.78 r11 = −32.13 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −16.531 d13 = 0.9 Nd13 = 1.51823 νd13 = 58.9 r14 = 7.005 d14 = 1.57 Nd14 = 1.8061 νd14 = 40.92 r15 = 21.588 d15 = D15 r16 = 14.073 d16 = 3.44 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 1.56 Nd17 = 1.84666 νd17 = 23.78 r18 = −20.07 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = 4.66886E−05 A6 = −3.68390E−07 A8 = 0  6th surface k = 0 A4 = 4.41308E−05 A6 = −1.09516E−08 A8 = 0.00000E+00  9th surface k = 0 A4 = −3.06648E−05 A6 = −2.07782E−08 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.41284E−04 A6 = −9.64511E−07 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.099 13.417 17.991 FNO. 3.26 3.52 4.58 D8 13.95 3.68 0.4 D11 0.4 12.53 12.79 D12 1.57 4.97 12.55 D15 6.19 5.04 3.12 D18 5.41 2.24 1.07 D22 1.36 1.36 1.36

Thirty Fifth Embodiment

FIG. 69 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty fifth embodiment of the present invention.

FIG. 70A, FIG. 70B, and FIG. 70C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty fifth embodiment, where, FIG. 70A shows the state at the wide angle end, FIG. 70B shows the intermediate state, and FIG. 70C shows the state at the telephoto end.

The zoom lens of the thirty fifth embodiment, as shown in FIG. 69, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty fifth embodiment will be enumerated.

Numerical data 35 r1 = 30.82 d1 = 1.1 Nd1 = 1.68184 νd1 = 39.35 r2 = 10.5 d2 = 0.35 Nd2 = 1.59885 νd2 = 6.52 r3 = 10.648 d3 = 4.65 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 134.153 d6 = 3.23 Nd6 = 1.82682 νd6 = 41.39 (Aspheric surface) r7 = −12.852 d7 = 0.7 Nd7 = 1.54352 νd7 = 51.79 r8 = 17.506 d8 = D8 r9 = 19.026 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −34.264 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −18.881 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 6.389 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 20.689 d15 = D15 r16 = 13.519 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −33.096 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = 6.29124E−05 A6 = −9.94304E−08 A8 = 0  6th surface k = 0 A4 = 3.57536E−05 A6 = −2.19825E−07 A8 = 0.00000E+00  9th surface k = 0 A4 = −2.33627E−05 A6 = 1.44142E−07 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.46902E−04 A6 = −2.18220E−06 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.421 17.996 FNO. 3.36 3.86 4.73 D8 23.43 6.51 1.75 D11 1.47 10 10.6 D12 0.53 6.33 13.1 D15 6.2 5.15 3.36 D18 5.4 2.12 0.82 D22 1.36 1.36 1.36

Thirty Sixth Embodiment

FIG. 71 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty sixth embodiment of the present invention.

FIG. 72A, FIG. 72B, and FIG. 72C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty sixth embodiment, where, FIG. 72A shows the state at the wide angle end, FIG. 72B shows the intermediate state, and FIG. 72C shows the state at the telephoto end.

The zoom lens of the thirty sixth embodiment, as shown in FIG. 71, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L242 in the fourth lens group G4.

Next, numerical data of the thirty sixth embodiment will be enumerated.

Numerical data 36 r1 = 31.869 d1 = 1.1 Nd1 = 1.68455 νd1 = 38.62 r2 = 10.5 d2 = 0.35 Nd2 = 1.79525 νd2 = 9.95 r3 = 10.719 d3 = 4.19 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 99.427 d6 = 3.24 Nd6 = 1.82739 νd6 = 42.49 (Aspheric surface) r7 = −13.299 d7 = 0.7 Nd7 = 1.54227 νd7 = 52.3 r8 = 16.692 d8 = D8 r9 = 19.193 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −33.527 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −18.855 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 6.427 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 21.117 d15 = D15 r16 = 14.070 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −30.061 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = 5.65707E−05 A6 = −8.35153E−09 A8 = 0  6th surface k = 0 A4 = 4.41416E−05 A6 = −2.42655E−07 A8 = 0.00000E+00  9th surface k = 0 A4 = −2.48396E−05 A6 = 1.43316E−07 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.47665E−04 A6 = −2.52326E−06 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.42 17.995 FNO. 3.35 3.84 4.67 D8 23.69 6.89 2.16 D11 1.33 9.95 10.69 D12 0.53 6.23 12.79 D15 6.2 5.15 3.38 D18 5.4 2.12 0.81 D22 1.36 1.36 1.36

Thirty Seventh Embodiment

FIG. 73 is a cross-sectional view along the optical axis showing an optical arrangement at the wide angle end of a zoom lens according to a thirty seventh embodiment of the present invention.

FIG. 74A, FIG. 74B, and FIG. 74C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty seventh embodiment, where, FIG. 74A shows the state at the wide angle end, FIG. 74B shows the intermediate state, and FIG. 74C shows the state at the telephoto end.

The zoom lens of the thirty seventh embodiment, as shown in FIG. 73, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G2, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty seventh embodiment will be enumerated.

Numerical data 37 r1 = 36.23 d1 = 1.1 Nd1 = 1.69029 νd1 = 36.36 r2 = 10.5 d2 = 0.35 Nd2 = 1.9712 νd2 = 12.88 r3 = 11.000 d3 = 3.93 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 88.421 d6 = 2.2 Nd6 = 1.82354 νd6 = 44.73 (Aspheric surface) r7 = −14.187 d7 = 0.7 Nd7 = 1.53704 νd7 = 54.58 r8 = 16.455 d8 = D8 r9 = 18.958 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −32.852 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −18.113 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 6.38 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 20.833 d15 = D15 r16 = 13.828 d16 = 3.5 Nd16 = 1.7432 νd16 = 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −29.055 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = 5.07303E−05 A6 = −6.94190E−08 A8 = 0  6th surface k = 0 A4 = 4.89135E−05 A6 = −2.70777E−07 A8 = 0.00000E+00  9th surface k = 0 A4 = −2.69831E−05 A6 = 1.67783E−07 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.51906E−04 A6 = −2.58667E−06 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.106 13.426 18.001 FNO. 3.32 3.76 4.59 D8 22.99 6.9 2.3 D11 1.19 10.06 10.8 D12 0.53 5.88 12.39 D15 6.19 5.13 3.33 D18 5.4 2.14 0.85 D22 1.36 1.36 1.36

Thirty Eighth Embodiment

FIG. 75 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty eighth embodiment of the present invention.

FIG. 76A, FIG. 76B, and FIG. 76C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty eighth embodiment, where, FIG. 76A shows the state at the wide angle end, FIG. 76B shows the intermediate state, and FIG. 76C shows the state at the telephoto end.

The zoom lens of the thirty eighth embodiment, as shown in FIG. 75, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a cemented lens which is formed by a negative meniscus lens L211 having a convex surface directed toward the object side and a positive meniscus lens L212 having a convex surface directed toward the object side, a prism L213, and a cemented lens which is formed by a biconvex lens L214 and a biconcave lens L215, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the image side of the positive meniscus lens L212 having the convex surface directed toward the object side and a surface on the object side of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty eighth embodiment will be enumerated.

Numerical data 38 r1 = 31.999 d1 = 1.1 Nd1 = 1.71082 νd1 = 36.25 r2 = 10.5 d2 = 0.35 Nd2 = 2.0512 νd2 = 6.28 r3 = 10.544 d3 = 4.21 (Aspheric surface) r4 = ∞ d4 = 12.5 Nd4 = 1.8061 νd4 = 40.92 r5 = ∞ d5 = 0.4 r6 = 81.783 d6 = 2.2 Nd6 = 1.81694 νd6 = 45.25 (Aspheric surface) r7 = −15.2 d7 = 0.7 Nd7 = 1.53247 νd7 = 56.77 r8 = 16.515 d8 = D8 r9 = 18.404 d9 = 3.5 Nd9 = 1.7432 νd9 = 49.34 (Aspheric surface) r10 = −13 d10 = 0.7 Nd10 = 1.84666 νd10 = 23.78 r11 = −33.096 d11 = D11 r12 = Aperture stop d12 = D12 r13 = −16.544 d13 = 0.7 Nd13 = 1.51823 νd13 = 58.9 r14 = 6.208 d14 = 1.6 Nd14 = 1.8061 νd14 = 40.92 r15 = 20.648 d15 = D15 r16 = 12.668 d16 = 3.5 Nd16 = 1.7432 νd16−= 49.34 (Aspheric surface) r17 = −6 d17 = 0.7 Nd17 = 1.84666 νd17 = 23.78 r18 = −34.221 d18 = D18 r19 = ∞ d19 = 1.44 Nd19 = 1.54771 νd19 = 62.84 r20 = ∞ d20 = 0.8 r21 = ∞ d21 = 0.6 Nd21 = 1.51633 νd21 = 64.14 r22 = ∞ d22 = D22 Aspherical coefficients  3rd surface k = 0 A4 = 3.63151E−05 A6 = −1.62265E−07 A8 = 0  6th surface k = 0 A4 = 4.72473E−05 A6 = −1.61277E−07 A8 = 0.00000E+00  9th surface k = 0 A4 = −2.67300E−05 A6 = 1.00083E−07 A8 = 0.00000E+00 16th surface k = 0 A4 = −1.61823E−04 A6 = −2.44296E−06 A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1st surface) is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.42 17.995 FNO. 3.3 3.75 4.63 D8 21.27 6.21 1.88 D11 1.45 10.47 11.12 D12 0.54 5.9 12.67 D15 6.19 5.11 3.29 D18 5.4 2.16 0.9 D22 1.36 1.36 1.36

Thirty Ninth Embodiment

Thus, it is possible to use such image forming optical system of the present invention in a photographic apparatus in which an image of an object is photographed by an electronic image pickup element such as a CCD and a CMOS, particularly a digital camera and a video camera, a personal computer, a telephone, and a portable terminal which are examples of an information processing unit, particularly a portable telephone which is easy to carry. Embodiments thereof will be exemplified below.

In FIG. 77 to FIG. 79 show conceptual diagrams of structures in which the image forming optical system according to the present invention is incorporated in a photographic optical system 41 of a digital camera. FIG. 77 is a frontward perspective view showing an appearance of a digital camera 40, FIG. 78 is a rearward perspective view of the same, and FIG. 79 is a cross-sectional view showing an optical arrangement of the digital camera 40.

The digital camera 40, in a case of this example, includes the photographic optical system 41 (an objective optical system for photography 48) having an optical path for photography 42, a finder optical system 43 having an optical path for finder 44, a shutter 45, a flash 46, and a liquid-crystal display monitor 47. Moreover, when the shutter 45 disposed at an upper portion of the camera 40 is pressed, in conjugation with this, a photograph is taken through the photographic optical system 41 (objective optical system for photography 48) such as the zoom lens in the first embodiment.

An object image formed by the photographic optical system 41 (photographic objective optical system 48) is formed on an image pickup surface 50 of a CCD 49. The object image photoreceived at the CCD 49 is displayed on the liquid-crystal display monitor 47 which is provided on a camera rear surface as an electronic image, via an image processing means 51. Moreover, a memory etc. is disposed in the image processing means 51, and it is possible to record the electronic image photographed. This memory may be provided separately from the image processing means 51, or may be formed by carrying out by writing by recording (recorded writing) electronically by a floppy (registered trademark) disc, memory card, or an MO etc.

Furthermore, an objective optical system for finder 53 is disposed in the optical path for finder 44. This objective optical system for finder 53 includes a cover lens 54, a first prism 10, an aperture stop 2, a second prism 20, and a lens for focusing 66. An object image is formed on an image forming surface 67 by this objective optical system for finder 53. This object image is formed in a field frame of a Porro prism which is an image erecting member equipped with a first reflecting surface 56 and a second reflecting surface 58. On a rear side of this Porro prism, an eyepiece optical system 59 which guides an image formed as an erected normal image is disposed.

By the digital camera 40 structured in such manner, it is possible to realize an optical image pickup apparatus having a zoom lens with a reduced size and thickness, in which the number of structural components is reduced.

Next, a personal computer which is an example of an information processing apparatus with a built-in image forming system as an objective optical system is shown in FIG. 80 to FIG. 82. FIG. 80 is a frontward perspective view of a personal computer 300 with its cover opened, FIG. 81 is a cross-sectional view of a photographic optical system 303 of the personal computer 300, and FIG. 82 is a side view of FIG. 80. As it is shown in FIG. 80 to FIG. 82, the personal computer 300 has a keyboard 301, an information processing means and a recording means, a monitor 302, and a photographic optical system 303.

Here, the keyboard 301 is for an operator to input information from an outside. The information processing means and the recording means are omitted in the diagram. The monitor 302 is for displaying the information to the operator. The photographic optical system 303 is for photographing an image of the operator or a surrounding. The monitor 302 may be a display such as a liquid-crystal display or a CRT display. As the liquid-crystal display, a transmission liquid-crystal display device which illuminates from a rear surface by a backlight not shown in the diagram, and a reflection liquid-crystal display device which displays by reflecting light from a front surface are available. Moreover, in the diagram, the photographic optical system 303 is built-in at a right side of the monitor 302, but without restricting to this location, the photographic optical system 303 may be anywhere around the monitor 302 and the keyboard 301.

This photographic optical system 303 has an objective optical system 100 which includes the zoom lens in the first embodiment for example, and an electronic image pickup element chip 162 which receives an image. These are built into the personal computer 300.

At a front end of a mirror frame, a cover glass 102 for protecting the objective optical system 100 is disposed.

An object image received at the electronic image pickup element chip 162 is input to a processing means of the personal computer 300 via a terminal 166. Further, the object image is displayed as an electronic image on the monitor 302. In FIG. 40, an image 305 photographed by the user is displayed as an example of the electronic image. Moreover, it is also possible to display the image 305 on a personal computer of a communication counterpart from a remote location via a processing means. For transmitting the image to the remote location, the Internet and telephone are used.

Next, a telephone which is an example of an information processing apparatus in which the image forming optical system of the present invention is built-in as a photographic optical system, particularly a portable telephone which is easy to carry is shown in FIG. 83A, FIG. 83B, and FIG. 83C. FIG. 83A is a front view of a portable telephone 400, FIG. 83B is a side view of the portable telephone 400, and FIG. 83C is a cross-sectional view of a photographic optical system 405. As shown in FIG. 83A to FIG. 83C, the portable telephone 400 includes a microphone section 401, a speaker section 402, an input dial 403, a monitor 404, the photographic optical system 405, an antenna 406, and a processing means.

Here, the microphone section 401 is for inputting a voice of the operator as information. The speaker section 402 is for outputting a voice of the communication counterpart. The input dial 403 is for the operator to input information. The monitor 404 is for displaying a photographic image of the operator himself and the communication counterpart, and information such as a telephone number. The antenna 406 is for carrying out a transmission and a reception of communication electric waves. The processing means (not shown in the diagram) is for carrying out processing of image information, communication information, and input signal etc.

Here, the monitor 404 is a liquid-crystal display device. Moreover, in the diagram, a position of disposing each structural element is not restricted in particular to a position in the diagram. This photographic optical system 405 has an objective optical system 100 which is disposed in a photographic optical path 407 and an image pickup element chip 162 which receives an object image. As the objective optical system 100, the zoom lens in the first embodiment for example, is used. These are built into the portable telephone 400.

At a front end of a mirror frame, a cover glass 102 for protecting the objective optical system 100 is disposed.

An object image received at the electronic image pickup element chip 162 is input to an image processing means which is not shown in the diagram, via a terminal 166. Further, the object image finally displayed, as an electronic image on the monitor 404 or a monitor of the communication counterpart, or both. Moreover, a signal processing function is included in the processing means. In a case of transmitting an image to the communication counterpart, according to this function, information of the object image received at the electronic image pickup element chip 162 is converted to a signal which can be transmitted.

As it has been described above, the image forming optical system of the present invention, and the electronic image pickup apparatus in which the image forming optical system is used have the following characteristics.

(1) It is characterized in that, instead of condition (1a), the following conditional expression is satisfied. 1.48<Nd<2.04 Here, Nd denotes a refractive index of a glass used in a cemented lens, νd denotes an Abbe's number for the glass used in the cemented lens, and a relation Nd=α×νd+β is satisfied. (2) It is characterized in that, instead of condition (1a), the following conditional expression is satisfied. 1.50<β<2.00 Here, Nd denotes a refractive index of the glass used in the cemented lens, νd denotes the Abbe's number for the glass used in the cemented lens, and the relation Nd=α×νd+β is satisfied. (3) It is characterized in that, instead of condition (2a), the following conditional expression is satisfied. 1.58<Nd<2.10 Here, Nd denotes the refractive index of the glass used in the cemented lens. (4) It is characterized in that, instead of condition (2a), the following conditional expression is satisfied. 1.63<Nd<1.95 Here, Nd denotes the refractive index of the glass used in the cemented lens. (5) It is characterized in that, instead of condition (3a), the following conditional expression is satisfied. 5<νd<10 Here, νd denotes the Abbe's number for the glass used in the cemented lens. (6) It is characterized in that, instead of condition (3a), the following conditional expression is satisfied. 6<νd<9 Here, νd denotes the Abbe's number for the glass used in the cemented lens. (7) It is characterized in that, instead of condition (1b), the following conditional expression is satisfied. 1.48<β<2.04 Here, Nd denotes the refractive index of the glass used in the cemented lens, νd denotes the Abbe's number for the glass used in the cemented lens, and the relation Nd=α×νd+β is satisfied. (8) It is characterized in that, instead of condition (1b), the following conditional expression is satisfied. 1.50≦β≦2.00 Here, Nd denotes the refractive index of the glass used in the cemented lens, νd denotes the Abbe's number for the glass used in the cemented lens, and the relation Nd=α×νd+β is satisfied. (9) It is characterized in that, instead of condition (2b), the following conditional expression is satisfied. 1.60<Nd<2.10 Here, Nd denotes the refractive index of the glass used in the cemented lens. (10) It is characterized in that, instead of condition (2b), the following conditional expression is satisfied. 1.63<Nd<1.95 Here, Nd denotes the refractive index of the glass used in the cemented lens. (11) It is characterized in that, instead of condition (3b), the following conditional expression is satisfied. 5<νd<30 Here, νd denotes the Abbe's number for the glass used in the cemented lens. (12) It is characterized in that, instead of condition (3b), the following conditional expression is satisfied. 6<νd<25 Here, νd denotes the Abbe's number for the glass used in the cemented lens. (13) It is characterized in that, instead of condition (7), the following conditional expression is satisfied at the time of almost infinite object point focusing. 0.75<y ₀₇/(fw·tan ω_(07w))<0.94

where, y₀₇ is indicated as y₀₇=0.7y₁₀ when, in an effective image pickup surface (surface in which, image pickup is possible), a distance from a center up to a farthest point (maximum image height) is let to be y₁₀. Moreover, ω_(07w) is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface at a wide angle end up to a position of y₀₇.

(14) It is characterized in that, instead of condition (7), the following conditional expression is satisfied at the time of almost infinite object point focusing. 0.80<y ₀₇/(fw·tan ω_(07w))<0.92

where, y₀₇ is indicated by y₀₇=0.7y₁₀ when, in an effective image pickup surface (surface in which, image pickup is possible), a distance from a center up to a farthest point (maximum image height) is let to be y₁₀. Moreover, ω_(07w) is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface in a wide angle end up to a position of y₀₇.

The present invention can have various modified embodiments which fall within the basic teachings herein set forth.

INDUSTRIAL APPLICABILITY

An image forming optical system according to the present invention is useful in an optical system with a reduced size and thickness, and furthermore, an electronic image pickup apparatus of the present invention is useful in an apparatus in which, both a favorable correction and a widening of an angle have been realized. 

1. An image forming optical system comprising: a positive lens group; a negative lens group; and an aperture stop, wherein the negative lens group is disposed at an object side of the aperture stop, and the negative lens group includes a cemented lens which is formed by cementing a plurality of lenses, and in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β where α=−0.017 is set, Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a) and a line when an upper limit value is in a range of the following conditional expression (1a), and an area determined by following conditional expressions (2a) and (3a): 1.45<β<2.15  (1a) 1.30<Nd<2.20  (2a) 3<νd<12  (3a) where Nd denotes a refractive index, and νd denotes an Abbe's number.
 2. An image forming optical system comprising: a positive lens group; a negative lens group; and an aperture stop, wherein the negative lens group is disposed at an object side of the aperture stop, and the negative lens group includes a cemented lens which is formed by cementing a plurality of lenses, and in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β where α=−0.017 is set, Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1b), and a line when an upper limit value is in a range of the following conditional expression (1b), and an area determined by following conditional expressions (2b) and (3b); 1.45<β<2.15  (1b) 1.58<Nd<2.20  (2b) 3<νd<40  (3b) where Nd denotes a refractive index, and νd denotes an Abbe's number.
 3. The image forming optical system according to one of claim 1 and claim 2, wherein when the one lens of which, Nd and νd are included in both the areas is let to be a predetermined lens, a center thickness of the predetermined lens along an optical axis of the predetermined lens is less than the center thickness along the optical axis of the other lens of the cemented lens.
 4. The image forming optical system according to claim 3, wherein the image forming optical system satisfies a following conditional expression 0.22<t1<2.0 where, t1 is a center thickness of the predetermined lens along an optical axis of the predetermined lens.
 5. The image forming optical system according to one of claim 1 and claim 2, wherein the cemented lens is a compound lens which is formed by closely adhering and hardening a resin on a lens surface of the one lens which forms the cemented lens.
 6. The image forming optical system according to one of claim 1 and claim 2, wherein the cemented lens is a compound lens which is formed by closely adhering and hardening a glass on a lens surface of the one lens which forms the cemented lens.
 7. The image forming optical system according to one of claim 1 and claim 2, wherein the image forming optical system is a zoom lens of which, a lens group on the closest side of an object is a positive lens group.
 8. The image forming optical system according to one of claim 1 and claim 2, wherein the image forming optical system is a zoom lens of which, a lens group on the closest side of an object is a negative lens group.
 9. The image forming optical system according to one of claim 1 and claim 2, comprising: a prism for folding.
 10. The image forming optical system according to claim 9, wherein the prism is in a lens group on the closest side of an object.
 11. An electronic image pickup apparatus comprising: an image forming optical system according to claim 1 or claim 2; an electronic image pickup element; and an image processing means which processes image data obtained by image pickup by the electronic image pickup element, of an image which is formed through the image forming optical system, and outputs as image data in which, a shape of the image is changed, wherein the image forming optical system is a zoom lens, and the zoom lens satisfies a following conditional expression at a time of an infinite object point focusing 0.7<y ₀₇/(fw·tan ω_(07w))<0.96 where, y₀₇ is indicated as y₀₇=0.7y₁₀ when, in an effective image pickup surface, a distance from a center up to a farthest point is let to be y₁₀ and, ω_(07w) is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface in a wide angle end up to a position of y₀₇. 